0625/22/F/M/26 | IGCSE PHYSICS PAPER 2 FEB MARCH 2026 | #igcse | #physics | #YTClassroom

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[00:00:00]Hello guys, welcome back to YT classroom. I hope you all are doing well. Today we'll be solving IGCSE physics paper 2 variant 2 from the Feb March 2026 series. This is the latest paper for IGCSE physics from the 2026 series and it is very important especially for the ones who are appearing for paper 2 in the May June 2026 series. If you're new to this channel, do not forget to like, share, and subscribe for more helpful content, especially for the ongoing May June 2026 series. Now, this paper has 40 questions and 45 minutes have been allotted for that. And calculators are allowed in this paper. So, take your calculators right now before we start solving. The weight of 1 kg is taken to be 9.8 Newtons and not 10 newtons. So, be careful on that. All right, let's get started.

[00:00:54]The diagram shows a stone of irregular shape. Which property of a stone can be found by lowering it into a measuring cylinder half filled with water. So let's say you have a measuring cylinder, right? That is half filled with water.

[00:01:10]Then when I'm going to put the stone inside, what happens is that the um the reading on the measuring cylinder will be over here. Let's say the rock is inside. So this is the new reading on the measuring cylinder. This is the previous reading on the measuring cylinder. So the difference between these two readings will tell us the volume of the irregular stone. That is why we will be able to get the volume.

[00:01:33]All right. Moving on. A helium balloon is t taped to a top balance to a top pen balance. A metal block of 100 g is placed on the balance. The reading on the balance is 91 g. Which statement can be deduced from the experiment? Now we have placed a metal block of 100 g on the balance where the reading is only 91 g. Now you need to understand that the reading on the balance is actually the resultant force on the balance. So 91 g.

[00:02:04]What is the force due to 91 g? 91 g is a mass that is going to be 0.0 91 kg right divided by,000. Okay. Okay.

[00:02:15]And if you do W is equal to mg, we can understand that the mass is 0.091 and the weight is 9.8. Using a calculator, 0.091 * 9.8 is 0.89.

[00:02:29]So the force on this thing on the top palance is actually 0.89 newtons. Okay.

[00:02:35]Now, how much force is the metal block applying? The metal block has a mass of 100 g. So 0.1, which is 100 g, multiplied by 9.8. 8 0.1 into 9.8 is going to be 0.98.

[00:02:49]So the metal block is applying a force of 0.98 Ntons. But the resultant force is only 0.89. That means the helium balloon must be exerting an upward force of 0.98US 0.89 which will be 0.09 Newton. So when you have this upward force being exerted by the helium balloon then only the resultant force on the on the balance would be 0.89 newtons. Let's check which option matches that. So that would be option D which says that the resultant downward force on the top balance is 0.89 newtons. So it turns out that we did not actually need to work out the other forces. Only knowing what force on the top balance is there would help you answer this question.

[00:03:31]An athlete runs 300 m up a hill in 100 seconds. She then runs down the same speeds the same hill in 50 seconds. What is the average speed for her whole run?

[00:03:43]So when she went up, she ran 300 m in 100 seconds. When she came down, she again ran 300 m in 50 seconds. So the total distance is 600 m. The total time is 150. That means the total speed will be 4 m/s.

[00:04:00]So the answer would be B. Therefore, the first three answers are C, D, and B.

[00:04:06]Moving on, the diagram shows a speed time graph for a car. What is the acceleration of the car? Acceleration is given by the final velocity minus the initial velocity over the time taken for this change in velocity. Final velocity is 12 and initial velocity is 4. So 12 - 4 divided by the time for which it takes is going to be 2 seconds because it's 2 over here that is 8 / 2 which will be 4 m/s 4 m/s squared. That is why the acceleration will be four. Question number five, what is weight? Now weight as we know it's a gravitational force.

[00:04:42]It's a force that acts on a mass that has been placed in a gravitational field. So weight is a gravitational force, not a frictional force, magnetic or electromagnetic force. What is the relationship between the force on an object, its mass and its acceleration?

[00:04:58]Now we know that the relationship is actually F is equal to MA. But if you look carefully nowhere on this all of the options is f is equal to m a given.

[00:05:07]Let's rearrange the formula ourselves and then just match it up. That becomes much more easier. M will be equal to f / a and a will be equal to f / m. So we can see that the third formula 6 c which is m is equal to f / a matches this one exactly. Okay. So option is or the right option is c. Which statement about the resultant force acting on a moving object must be correct? Now we know that the resultant force the option A says that it is a change in the momentum of the object per unit time. Now that is actually true because force into the time for which it acts is equal to the change in momentum and this force does have to include the resultant force. So that we can consider the impact of only one force on the object's momentum. So that is why this particular formula it is the I mean resultant force. So force is indeed equal to change in momentum over change in time which is the rate of change of momentum per unit time. So 7 A would be the right answer. B would not be the right answer because it says that it is the force needed to keep the object moving at a constant speed. If a object is moving at constant speed, it does not actually need a force acting on it. It is the impulse acting on an object to keep the object moving. Not fully, right? um the object might be accelerating, the object might be in a constant speed and there's no force etc. So you don't know about that it is the largest forward force acting on the object. No, it is the force that is the effect of all the forces that are acting on the objects. All right. So the answers for this particular page are AC Ca Acca.

[00:06:45]Moving on. A motor is used to lift different size loads through the same vertical height. The power input to the motor is kept constant. The graph of time taken against load lifted is shown.

[00:06:58]Which statement about the efficiency of the motor is correct? So in this in this graph we can basically see the relationship between the time taken and how much load is lifted. And we can see that as the load lifted is increasing the time taken to load is also increasing. Okay. Now the input power is the same. And what they want us to comment on is actually the efficiency.

[00:07:17]Now if you think about it, some people might say that the efficiency is constant because the gradient of the graph is constant. But we will not be able to determine any information regarding efficiency or comment on any information the efficiency without having the values of the load lifted or the values of the time taken because those would tell us that at what rate is the load lifted increasing and as at what rate is the time increasing? Only if the load drift and time are increasing proportionally then we could say the efficiency is constant.

[00:07:48]Otherwise the efficiency might be increasing or might be decreasing. That is why we will need more information to determine this particular uh this particular value or about the efficiency.

[00:08:00]An object is at a depth h below the surface of a liquid. The density of the liquid is row and the gravitational field strength is g. What is the total pressure at depth h? Now pressure is actually equal to P. Pressure is actually equal to row which is the density of the liquid into G which is the gravitational field strength into H.

[00:08:21]This formula is covered in your syllabus. So obviously the answer would be that pressure is equal to row GH.

[00:08:27]They've replaced it with H. Row G says the same thing.

[00:08:31]Question number 10. A car tire runs over a nail that makes a hole in it. Now and because of that hole, the air the tire is actually leaking out. Why does the air leave the tire? Now the main reason why the air is actually leaving the tire is because of the pressure difference between the outer like outside the tire and inside the tire. Inside the tire the pressure is very high compared to outside the tire. And this higher pressure forces the molecules to move from the region of higher pressure to the lower pressure which is outside the region. That high pressure is kind of pushing the particles and that is why we would say that the pressure inside the tire being greater than the pressure outside is the reason why the air is actually leaving the tires. It is 10 A.

[00:09:16]Moving on. Which graph shows the relationship between the pressure and the volume for a fixed mass of gas at a constant temperature? Now we know that if you do have a fixed mass of gas at a constant temperature, pressure and volume are inversely proportional. That means that when the pressure increases the volume decreases and when the volume increases um they're inversely proportional that means if the pressure increases the volume decreases the volume increases the pressure decreases if it's at a constant temperature. So normally the graph for pressure and volume would look something like this and that is what I'm assuming a lot of candidates have made a mistake of choosing D. D is not the right answer because they say that it's 1 / volume it's not volume. So when they replaces one over volume what happens is that the graph is actually going to be this one.

[00:10:02]Now if you think about it in this graph we understand that as the value of P increases the value of 1 / V is also going to increase and if 1 / V increases that means the value of V will actually fall which supports that P and V are inversely proportional to each other.

[00:10:20]That is why we choose the right answer as C.

[00:10:23]All right, moving on.

[00:10:25]The graph shows that how the internal energy of 1 kg of a metal changes with temperature. So at various temperatures, how does the internal energy of 1 kg of metal change? What is the increase in the internal energy of the block of the same metal if it's 0.125 kg? So the graph is about 1 kg object. But what if you have a 0.125 kg object? When the temperature is raised from 40° to 80°.

[00:10:51]Now at 80° which is over here, let's look at this part first. Your energy is about over here. Okay, so that's 824 and this is in kiloj. So 8 to4,000 at 40° which is over this point you are at 812,000 812,000.

[00:11:16]So the difference between both of them is actually going to be 12,000 Jew.

[00:11:22]Okay. Now, but this 12,000 Jew is actually for 1 kg object. I'm only investigating a 0.125 kg object. That is why I will actually multiply this with 0.125 kg to get information about the 0.125 kg object. 12,000 multiplied by 0.125 is actually 1,500.

[00:11:43]That is why the increase in the internal energy for the same block of metal is going to be 1,500 Jew. The answer is going to be C. And I hope that is um that is understood.

[00:11:55]Both boiling and melting require an input of energy. What happens to the temperature of the water during the boiling and melting? Now at the particular point when a liquid is boiling or when a solid is melting there is no change in the temperature because the heat source or the energy is actually used to break the intermolecular forces between the particles so that they can move away from each other and start to move much more freely. That is why we would say that the temperature would remains unchanged during melting and during boiling. 13 D 14 A beaker contains a liquid. As the liquid evaporates, the particles escape from the surface of the liquid and the temperature of the liquid beaker changes. Which statement is correct?

[00:12:41]Now, they're all talking about the beaker being heated up or cooled down.

[00:12:45]What you need to understand is in evaporation, the particles that evaporate are the ones with the highest energy. That means the particles which are remaining have lower energy which leaves the liquid or the container in which the liquid is stored in bit cooler. That is why we would say that the beaker will cool down because the more energetic particles are going to escape from the surface of the liquid.

[00:13:06]Not every particle escapes only the with the ones with the most energy. So the remaining particles have lower energy.

[00:13:12]That's what causes the beaker to cool down.

[00:13:16]Equal volumes of water at 100° are put in four containers.

[00:13:21]Two containers have matte black sides and two containers have shiny white sides. One of each of two one of each type of container has a lid. The containers are left for 2 minutes. Which container or water has the highest temperature. Now in this particular case you need to understand the difference between emission thermal radiation being emitted between black matte black surfaces and shiny white surfaces. Now black are the best absorber and the best emitter. That is why black would lose a lot of energy. It would emit a lot of thermal radiation which would lead to loss of a lot of energy. Whereas white or shiny white is a poor absorber and a poor reflector. That means poor absorber and a poor em it has a lower rate of energy loss. That is why it will be able to keep the water at the highest temperature. These both will cool down quickly. So we cannot take them. Now between C and D, should we choose the one with a lid or one without the lid? Obviously, we'll be choosing the one with the lid because the lid will prevent convection currents being formed and that will prevent the heat being from being escaped or it will store the heat inside the container.

[00:14:29]That is why the correct answer would be 15D. That is the shiny white container with lid on.

[00:14:37]The diagram shows a person keeping warm while the water in the metal kettle the water in a metal kettle boils over a wood fire. Which thermal energy rad transfers are taking place in this particular situation. Now from the heat to the kettle, it's actually radiate.

[00:14:54]It's actually going to be conduction or yeah it's probably going to be conduction considering the fact that the heat is going to touch the um whatever the pot is made up of the metal pot, right? So it's transferring energy through um the particle vibrations and that is what conduction is. There'll obviously be convection currents because it says the person is keeping himself warm. So this is a hot air and it rises and it cools it goes over to this person like creating a convection current. So convection is also taking place and what about radiation? Obviously because this is a fire so fire will obviously be having radiation. So that is why the correct answer would be a which includes conduction, convection and radiation.

[00:15:34]radiation being from the fire to the person and fire to the surroundings as well.

[00:15:40]Question number 17. Which letter represents the amplitude and which res letter represents the wavelength of the wave? Now the amplitude is defined as the maximum displacement and the equilibrium position. This line is what we just defined as equilibrium.

[00:15:56]That means that the amplitude from this line to the maximum displacement which has been labeled to as s. So the amplitude is s a and b are not correct.

[00:16:06]What about the wavelength? Now wavelength is the distance between two points which are on consecutive waves.

[00:16:11]Such as if you take this point then there's a complete wave that's going on for starting from here. It goes up like this and it comes back down over here.

[00:16:19]So the wave is completed over here and this is what we call as one wavelength of one time period. Therefore it is R.

[00:16:25]And the final answer would be 17 DSR.

[00:16:30]Which statement about the image of an object formed in a plane mirror is correct? Now a plane mirror is the one that you use in your everyday lives. And we have one thing that we know that in a plane mirror the object is the same size as the image or the image is the same size as the object. So it would be 18b.

[00:16:50]Now in a lot of people got confused between this option and option D which is inverted.

[00:16:55]To be honest, yes, the images are inverted, but they're laterally inverted. And unless lateral is mentioned over here, this option would not be correct. Let's say we did not have this option, then that might option might have been correct. But one thing we know for sure that we can now see ourselves is that the image of an object is the same size as the object itself.

[00:17:16]Therefore, it's 18b.

[00:17:19]19. A ray of light travels from air into a glass block. So the speed of the ray is lamb it was VA and VG. The wavelength of ray is lambda A and lambda G and the frequency is F and FG. Three suggestions as as to how the reflective index of the glass may be calculated. First suggestion is VA which is the speed of ray over VG which is the speed of ray in glass and A is for speed of ray in the air. The wavelength of ray are lambda and lambda and the frequencies F and F.

[00:17:49]Now refractive index normally is done by the angle of incidence over the angle of um whatever we call reflection right wait have they given us the speeds VA and VG so the speed of the ray so the speed of the ray in air is VA and glass is VG that means we can use the speed values to find out the refractive index which is going to be N is equal to VA over VG this is correct the first option is correct the second option lambda yes indeed we can also to use lambda over here. So lambda would work. The third option n is equal to fa / fg. This won't however work because um the lambda values do not change when you are between two different materials. So this is not going to work and that's why you'll have 19b which is 1 and 2 only.

[00:18:37]A light travels from air into glass. The angle of incidence is 32° and the angle of refle refraction is 21.1°.

[00:18:45]What is the refractive index of the glass? Now for this you'll have to use the formula for the refractive index which is going to be s of the angle of incidence. Let's just say angle a divided by s of the angle of refraction.

[00:19:06]So sine of 32.0 over sine of 21.2 is actually 1.47 which is going to be 20 C.

[00:19:15]A real image of an object is formed by a converging lens. Which statement is correct? Now before we look at the statement, we have to understand this particular diagram. This is what you call as a lens diagram. Yeah, this is for how lenses work. Now for a real image, what exactly happens is if you remember you have a one straight line passing through here and then you have the other line which is passing through the focus point and then goes like this.

[00:19:43]And this is where your image is being performed. So in option A it says that the rays from the tip of the object that means from this particular point they do meet and find the image can be viewed on a screen. Yes, because this is a real image you will be able to view the image on the screen. That's why it's going to be 21A 22. Intruder alarms, mobile phones and security scanners are practical uses of electromagnetic radiation.

[00:20:10]which list places uh places the devices in the correct order of increasing wavelength of the electromagnetic radiation used. Now security scanners mostly use X-rays. So X-rays are at the bottom of your electromagnetic spectrum and that is why they are least likely to be suspected. Okay. So security scanners would be the the one with the lowest wavelength. That is why we cannot have B and A because we have security scanners.

[00:20:37]Now after that let's look at the second point. It says intruder alarms and mobile phones. Now intruder alarms mostly use thermal imaging. That is why we have we start off with radio radio microwaves and infrared right and the wavelength is actually increasing in this particular direction. Lambda lambda is increasing.

[00:21:04]So phones mostly use microwaves or radio waves and therefore security intruder alarms on the other hand they use infrared or thermal imaging. So that is why I'm going to give it to security scanners followed by intruder alarms followed by mobile phones that would be 22C.

[00:21:22]A student wants to explain why the sound from a train gets louder when it gets closer. Which type of wave and which property of the wave causes it to be louder? The main reason why the train gets actually louder when it comes is because now you need to understand that when the train is you know it's traveling on the track it's making a lot of sound and that sound disperses a lot of energy when it passes through different areas or when it hits a building etc. So that's why we see hear a very less sound unless we're in direct contact or very very close to it. On the other hand, when the train comes closer to you, what happens is that you hear the lar larger part of the amplitude, which makes it seem much more louder.

[00:22:01]Therefore, the answer would be 23B, which is the sound wave is a longitudinal wave. And the property is that the wave has a larger amplitude.

[00:22:10]23B. Moving on to question number 24. It says that the diagram shows four different sound waves as represented by an oscilloscope.

[00:22:20]The scales are the same in all the diagrams. Which sound has the lowest pitch. Now the lowest pitch will basically have the lowest frequency.

[00:22:35]Right? The lowest pitch will have the lowest frequency and the lowest frequency means the highest time period. The highest time period. So if I wanted to select the sound with the lowest pitch then I should have the highest time period and that time period is basically the time for the wave to complete one particular oscillation. So here I can see that B has the largest time period which is about these many boxes from starting from here and then going all the way up to here. If you look at all the other ways let's look at A. It is only covering this much of distance. So it's a very small time period. If you look over here, this is four boxes. But in B, it is about five and something boxes. It is more than five. If you look at D, it is only two boxes. That's why A is not correct. C is wrong and D is wrong. And B is the right option because it has the highest time period and so it will have the lowest frequency and therefore it will have the lowest pitch.

[00:23:40]A soft iron bar is not magnetized. it is held close to the north pole of a magnet and then to the south pole of the same magnet. What will be the result? Now a soft bar will basically mean that it can be magnetized quickly.

[00:23:56]So when something can basically be magnetized quickly that means that for example when I held it close to the north pole of the magnet there's a south pole induced on the soft iron bar so that it will try to attract it. Right?

[00:24:12]Then when you move the south pole of the same magnet towards it, it then quickly changes to the north pole and because it is a soft magnetic material, it can do that very very quickly. So when you keep it closer to the north pole, it will attract the north pole. When you close it to attract keep it closer to the south pole, it will attract the south pole. It will not hold that north pole charge for a very very long time. It will quickly change that to a south pole. So it can attract the south pole as well. That is why it is north pole and south pole both being attracted. 25e 26.

[00:24:46]Which quantity is defined as the energy transferred by a cell in driving a unit charge around the complete circuit? So obviously we know that a charge it gains energy from the cell to move around the complete circuit and then it uses up all of the energy. Now when it gains that energy that energy is called as the potential difference which is the energy transferred to the cell around the to so that it can move around the complete circuit and when it does does the work against the components and that's basically what we call as a potential difference. So therefore the quantity which is defined as the energy transferred by a cell and driving the units join in a complete circuit is called as the electromotive force and this is provided by the battery or the power cells to the cell. 26B 27. Which graph shows the relationship between the current and the voltage for a metal wire at a constant temperature?

[00:25:39]Now we know that the V is actually equal to IIR. The voltage is equal to current into the resistance. That means V / I shall be equal to R, right? V / I shall be equal to R. Now for a metal wire that is at a constant temperature, the value of R is actually constant. It's not going to change. So the the ratio of V and I must not change. That means if they have a graph of V or I or I over V, it must have a constant gradient which I can see in part C. That is the gradient of the graph is constant. That means the value of the R which is the gradient of the graph is also constant. That's why 27 scene. The circuit diagrams show a cell connected to two diodes and a lamp in series. In which circuit does the lamp light up? Let's have a close look.

[00:26:27]In the first one, the current starts to move around here, but it quickly gets stopped over here because of the diode.

[00:26:32]So, A is not correct. Let's put wrong over here. Let's look at B. From here, it starts, it starts to move around, starts to move around. It can flow around here. It comes on the lamp. So, the lamp does glow. But then it cannot get through this past. So, it stops over here. That means B is also not correct.

[00:26:50]Moving on to C. C starts from here. It goes around. It goes like this. it comes back and then goes away. So C is indeed working. So we'll just go with on with C. Remember for a diode if it's in this particular direction the current will be allowed if it's going from here. But if it's going from here then it is not allowed. So 28 C. Now moving on 29.

[00:27:14]The diagram shows the battery connected to two resistors X and Y. Two volt meters are connected in series. So we have a battery. We have voltmeter 1 and voltmeter 2 which are connected to X which is a resistor and Y which is a resistor. The reading on voltmeter 1 is greater than the reading on the voltmeter 2. Which row about the current in the two resistors and the resistance of the two resistors is correct. Now the first thing that we need to understand is that because both of the resistors are connected in a CD circuit the current is same in both the resistors.

[00:27:47]That means C and D are completely wrong.

[00:27:50]Now if the reading on a particular voltmeter is higher than the reading on the other voltmeter in the same circuit, it suggests that there they have a higher resistance because when something has more resistance, it requires more energy or more work to be done for a charge to move through it. That is why voltmeter one must have a higher reading that has caused a larger reading on the voltmeter than voltmeter 2. So current is same but resistance of X is going to be higher than the resistance of resistance of X is higher than resistance of Y which is leading to the larger voltmeter reading in voltmeter 1 and therefore a smaller voltmeter reading in voltmeter 29B.

[00:28:31]Moving on to 30. The diagram shows the conductor WZ. Part of the conductor lies between two magnetic poles north and south. When the conductor is moved, the electrons are flowing along the conductor from Z to W. In which direction is the conductor moved. Now over here we'll have to apply the right hand rule because the current is being induced over here. Right? So in this particular case we'll have to use the right hand rule. Now it says that when the conductors move the electrons are flowing from Z to W. That means they're going from Z to W. But remember electron flow is not the direction of the conventional current. The conventional current will always flow in the opposite direction. That means conventional current is in this particular direction.

[00:29:16]This particular direction. And let's use our right hand. So the first finger points to the magnetic field which should be from the north to the south.

[00:29:24]The second finger shows the direction of the current which is actually going to be towards your um let's say just try to point it towards your Z depending on how you're actually holding your hand. Now from what I can see is that if I have a magnetic field right and if I have my current right the force is actually out of the paper towards the viewer that is why it's going to be 30D 30D I apologize but I'll not be able to show you my hand because of my setup but it's very simple you use your thumb for the force your index finger for the um magnetic field and your middle finger for the direction of the current as I've shown always remember electrons flow in the opposite direction to the current flow. So it's 30D which is out of the paper towards the viewer. The graph one shows the output from a AC generator. So there are two graphs on this graph one.

[00:30:19]There's one graph which goes like this and there's a second graph which has much higher PD values at much lower time periods. What changes can be made so that the generator produces output too.

[00:30:32]Now what you could do is you could increase the speed of the rotation only.

[00:30:37]What happens is when you increase the speed of the rotation remember the emf generated is directly proportional to the rate of change of the magnetic flux.

[00:30:44]So when you rotate it quickly the rate of change of magnetic flux increases.

[00:30:47]Therefore the potential difference or the value of the potential difference will also increase. Second thing when you increase the speed of the rotation the cycles will be much more quicker.

[00:30:56]Therefore the time period will also be less. That is why you choose this particular option. If you only increase the number of coils, the magnitude will increase but the time period will remain the same. That's why you cannot choose this.

[00:31:09]If you look at option B, increasing the magnetic field strength and decreasing the number of coils. If you decrease the number of coils, then your amplitude does not reach to such a large maximum value. That's why I'm moving to D 31D 32. The diagram shows a current carrying wire and a magnetic field. In which direction is the direction of the magnetic force on the wire? Now in this particular case, we'll be using the left hand rule because there's already a current in the wire. My index finger is pointing from the north to the south. My middle finger is pointed direction at the current. And because of this very very weird position, I can see that the direction of the magnetic force which is pointed toward by my thumb is actually towards B. That is why it's going to be 32B.

[00:31:52]Moving on, a transformer has a primary coil with 2,000 turns and a secondary coil with 10,000 turns. And it's a 100% efficient transformer.

[00:32:02]VP is the voltage across the primary coil and VS is the voltage across secondary coil. So we'll say that VP voltage or voltage across the secondary coil is equal to primary coil it has 10,000 turns and the secondary coil it has 2,000 turns. Or wait, no, we have flipped that up. The primary coil has 2,000 turns. The secondary coil has 10,000 turns. That means VP over VS is actually 2 / 10 which is 1 over 5.

[00:32:33]Right? Now what do we see in the for in the answers that the formula is given that VS is equal to VP into something.

[00:32:40]So I can say that VP over VS is equal to 1x 5. Therefore 5 VPS is equal to VS. Therefore VS is equal to 5 * the value of VP. That means option C and option D are disqualified. Now what about is and IP and five. Now we know that because it's 100% efficient IP into VP that is the current in the primary coil into the voltage across the primary coil should be the same as I is the current in the secondary coil over voltage in the secondary coil. Now we know that rather than writing VS we can write 5 * VP. So IP into VP is equal to I S into 5 * VP. So let's cancel out VP from this particular case VP.

[00:33:31]So what I have right now is IP is equal to um 5 * the value of I. So therefore I will be equal to 1 5 * the value of IP.

[00:33:45]So I is going to be 0.2 2 * TP.

[00:33:49]Therefore, the correct answer would be that 5 * the value of VP is equal to VS and is equal to 0.2 * the value of IP.

[00:33:58]33 is indeed being the diagram shows the scattering of alpha particles by a gold foil. Two observations are labeled that is a very most particles remain undelected and a very few particles are being you know seen changing their angles.

[00:34:15]Which conclusion is correct?

[00:34:18]Okay. Now the atom has no overall charge but that is completely wrong. We know because the atom has nucleus and the nucleus has the atom has no overall charge. The atom has an overall positive charge. Now this is completely wrong because the atom you normally then neutral it has no overall charge. Part C the atom is mostly empty space. Now this was one of the third conclusions that can be drawn from this particular experiment that is that the atom is mostly empty space. That is why the alpha particles most of them went straight through the gold foil although they should have been hindered by the presence of other um let's say particles but because atom is mostly empty space then we all could see that moving on to 35 a nucleide has a symbol 2311 na which statement about all the atoms of this nucleide is correct it has 11 protons 11 electrons and 23 - 11 which is 12 um nucleons. So we can see that because it has 11 protons it would be 35A 36. A student measures the count rate from a radioactive source. Which method should the student use to remove the contribution made by the background radiation? What you do is you try to measure the background radiation and then subtract it with your own reading so that you can actually get the univers the value that you're trying to find without the background radiation. So you measure the count rate due to the background radiation on its own and then subtract it from the measure subtract it from the measurement of the from the source. So first you measure the background radiation and then you subtract it with your own reading to find the actual um count not the background count but the actual count that would be 36 C 37. A beam of alpha particles is traveling in a straight line it enters a region where there's a field that deflects the alpha particles in a circular path as shown. what is the type of field and its direction on the diagram.

[00:36:17]So now for this particular case I'm going to be using my left hand rule and I have now the magnetic field or the electric field is something that we don't know. So we don't use our index fingers. All we do know is the direction of the force. Now remember this is alpha particles. So what you're going to try to do is you're going to try to work out what's going to happen for the beta part. I mean this is these are beta particles. What you going to do is you want to try to work it out for the alpha particles. So if beta particles are being deflected down, alpha particles are obviously being deflected up. Okay.

[00:36:50]So I have my um force magnetic field current. So I would say that my direction of the current which is the middle finger is towards the top of the page. Okay. Now what about the way they're entering? The way they're entering is going to be something like this. So it points towards the right.

[00:37:06]Okay. Okay. So when I have something pointing towards the right, then where does my magnetic field act? Here you have to check your index finger. Okay.

[00:37:14]So again your middle finger will be pointing towards the top of the page which is going to be something or maybe let's say if you use our left hand then the middle finger is going to go towards away from you. It points away from you.

[00:37:28]What about your index finger? Your index finger will tell the direction of the magnetic field or the electric field.

[00:37:34]And the beta particles they're traveling um towards the left.

[00:37:40]Wait, the beta particles are traveling towards the left. So where exactly does it enter? As far as I can see, my finger actually is points towards the bottom of the page or that is into the page. That is why there would be a magnetic field into the page. 37 C. Okay. So you just have to use your hand over here. You have three fingers. You're going to use the middle finger to show the direction of the current which will be towards the top of the page. The reason I'm doing this is because when you do this particular experiment with your hand, it only works for the positively charged particles.

[00:38:18]All right? So, point that to the right direction. Then we'll have your finger, the index finger, which will tell you the direction of the magnetic field. And you will show the direction the beta particles or the alpha particles are entering in through your thumb. Okay?

[00:38:32]Okay, so they're entering. Then I have my middle finger which points towards this side and I have my magnetic field which points towards into the page.

[00:38:41]Okay, I hope that is correct. If you're wondering why it's a magnetic field and why not electric field, you got to think about this. If I have my beta particles moving down, that means this side is positive possibly positively charged if it was electrostatically charged. So this must be negative. Now if you try to work it out using your own hand that is let's say that your the particles are entering normally that is the force is there the magnetic field is from the top to the bottom of the page you will see that the force is actually into the page not downwards that is why the electric field concept won't be working over here and you'll have to understand that it's a magnetic field 37 C 38 uranium 235 can undergo nuclear fusion in many ways which equation correctly shows a possible fision reaction unit 235.

[00:39:29]Now in a fusion reaction out of these four equations the one that will be correct is one that involves the right count of the nuclear numbers and the atomic numbers. On this side I have 236 235 + 1. On this side I have 141 + 92 + 3 * 1 that's 236.

[00:39:48]Let's check our atomic numbers as well.

[00:39:51]This is going to be 92. This is going to be 56 36 that's 92. That means this one is the valid option. For all the other equations, I've already checked there's some sort of errors. The arithmetic errors are there. That is why they won't be valid. And 38A is the right answer.

[00:40:08]A satellite is orbiting above the Earth's equator. It completes one orbit of the Earth every 24 hours. What is the orbital speed? So, the radius of the Earth is 6,400 km. The satellite is at 36,000 km above the Earth's surface.

[00:40:22]Orbital speed. Orbital speed is given by 2 pi r / t. So 2 * the value of p<unk> * the value of r. Now here the r actually means the distance between the planet earth and the satellite itself. That's going to be 6,400 km plus 36,000. Why 36,000? Because the satellite is 36,000 above the surface of the earth. So you have to include that distance and the radius of the earth itself because you are taking the point from the center of the earth.

[00:40:56]That's why we include 6,400 as well. The orbital speed. Okay. So let's do 2 pi * wait this is the orbital speed. Orbital speed= 2 pi r divided by the time period also right 2 pi r which is the distance divided by the time will give you the speed. The distance is now as they said it's going to do 24 hours. So 24 hours which have 60 minutes which have 60 seconds. Let's work this out as a calculator. 2 pi into 6,400 + 36,000 / 24 into 60 into 60. That's actually 3.1 km/s. So that is why the correct answer would be 39p.

[00:41:37]One nuclear reaction that occurs in the sun is responsible for most of the energy releases in the sun is actually nuclear fusion which allows hydrogen to be fused into helium. meanwhile releasing a lot of energy and because these both particles are positively charged it is very difficult to get them together and produce a large amount of energy but the sun because the the temperature or the extreme conditions of the sun these are also allowed that is why it would be 40t and with that ladies and gentlemen we have reached the end of this paper I hope this video was helpful if you have any doubts any comments any suggestions please do not forget to post down below I would really appreciate this and share this video with you with your friends as well. Till then, take care, good luck, and bye-bye.