NEET-2026 PHYSICS SOLVED QUESTIONS (Code-13).

Added: 2026-05-09

[00:00:04]Welcome to Cosmos Gap.

[00:00:07]I'm your host, Cosmos.

[00:00:11]We have been a bit late due to some urgent work.

[00:00:17]Today we'll be analyzing week 2026 physics questions.

[00:00:28]I'll be referring on code 13.

[00:00:32]The first question for a simple pendulum having time period t the variation of kinetic energy with time is represented by this this this.

[00:00:50]We'll try to take the correct answer to see which of this graph is the correct graph for our question.

[00:01:04]Let's take a pendulum here.

[00:01:11]This position is called as mean position.

[00:01:19]These two position these two position are called as extreme positions.

[00:01:27]We know that kinetic energy is given by kinetic energy of a simple pendulum is given by half m omega square a² minus y² where all the notation have their usual meanings.

[00:01:47]Now we know that at the mean position x sorry y equ= z and the kinetic energy is maximum. The kinetic energy is maximum. Whereas as our pendulum move towards the extreme position it stop for a very short period of time that means kinetic energy is going to be equal to zero. Similarly, as it come backs and comes here at the other extreme position, it will stop for a while and then goes back. So, kinetic energy is going to be zero.

[00:02:28]Now the displacement here while going this side let's take this is positive y whereas while coming back this side let's take it minus y because it is in the opposite direction.

[00:02:50]Now placing on placing one extreme position at the origin and the other extreme position as half cycle. We find that from here it is zero and it keeps on increasing till it reaches mean position and then decreases till it reaches the other extreme point that is for the half cycle.

[00:03:17]So it matches this one. But as I come here, even though the displacement is minus, I find that y has a square here. So which means this negative sign is not working because the square takes away the negative. So it will be the same as positive.

[00:03:41]So while coming back also the graph is going to be going up like the first cycle. So this one is not matching because the row one is not matching. It starts from zero. But here the starting point is not zero. So this option is omitted. This one we find that here the energy kinetic energy is zero. keeps on increasing and then it after reaching the main position it decreases. So there is a curve here but here the curve is not there.

[00:04:21]This one in the first half cycle it starts from zero. It goes up to the mean position comes down to the extreme position first cycle. second cycle from zero it goes up to the mean position and then comes back to the extreme position zero. So option four is going to be the correct answer.

[00:04:49]This is our second question.

[00:04:52]A room heater is rated 400 watt 220 volt. If the supply voltage drops to two to 200 volt, what will be the power consumed? We have to find the approximate value. The option are 400 watt, 121 watt, 331 watt and 200 watt.

[00:05:21]To approach this let's try to find the given things and find the current in the heater.

[00:05:32]In the first case power is given to be 400 watt volt is given to be 220 volt. I know that power is given by VI. So I is going to be equal to P by V. Putting the value of A and V 400 by 220.

[00:06:10]Canceling I get 20 by 11.

[00:06:15]I got the current passing through the H2.

[00:06:19]Now for the second case when the voltage drops to 200 volt but the questions does not says about the change of current. So the current remains the same. So second case Z is going to be 200 volt. I remains the same which is 20 by 11 aere. Now I want to find the power. So power equals VI. V is going to be 200 into I is going to be 20 by 11.

[00:06:59]So it's going to be 4,000 by 11. Let's try to divide this and see.

[00:07:24]So since the question asks me approximately and I find the option.

[00:07:30]So the question is saying about approximate value.

[00:07:36]So I get something around 363 watt.

[00:07:42]Now from the following option the nearest value approximate value to 363 is option number three 331 watt. So this should be the correct answer.

[00:08:00]The third question, the angular speed of a flywheel is increased from 600 RPM to 1200 RPM in 10 seconds.

[00:08:17]The number of revolution completed by the flywheel during this time is the option are 600 300 900 150.

[00:08:33]Let's try to find the solution here.

[00:08:39]Since the flying wheel is in a circular motion, we're going to approach it with uniform circular motion equations.

[00:08:51]So the first given thing is 600 RPM rotation per minute. So this is my first speed. So initial angular initial angular speed is given to be 600 RPM. I want to change this RPM into WS per second. So 600 into rotation into web is one revolution has 2 pi and per minute means minute change into seconds is 60.

[00:09:37]After cutting it I get 25 red per seconds.

[00:09:45]Similarly, the final RPM is going to be our final angular speed.

[00:09:56]So changing this to WS per second with the same concept.

[00:10:15]Now my time is given to me 10 seconds.

[00:10:22]Now from here I'll try to find the acceleration which is omega.

[00:10:29]So I'll use which is alpha.

[00:10:35]So I'll use the acceleration formula change in angular speed over time. So change in angular speed is final minus initial divided by time. Final is going to be 40<unk>i minus initial is going to be 20 pi / 100 divided by 10.

[00:11:07]20<unk> / 10.

[00:11:12]So the ex angular acceleration is 2 pi rad².

[00:11:22]Now in order to find my total revolution or number of revolution from 600 rpm to 12,000 rpm, I should know the distance how far it travels. So using the circular motion equation I'm going to use omega f² minus omega i² equals the following question to alpha. The change in displacement is going to be tak because it is going to be it is in circular motion. Now the value of this is 4 pi² minus 20 pi square = 2 into 2<unk>i delta.

[00:12:33]I try to calculate it. 1 6 0<unk>² - 4 0 0<unk>² = 4 pi delta theta I minus this I get 12 0 0 I square I bring this 4 pi to this side 4 pi equals delta theta 5 by cancel for 300. So it's going to be delta theta is going to be equal to 300 pi.

[00:13:18]Now to find the number of revolution the angular displacement divided by one full complete displacement. So number of revolution is going to be equal to del theta by 2 pi. So it's going to be 300 pi / 2 pi by p<unk> cancelled 2 1 5 0.

[00:13:50]So as I move from 600 RPM to 12,000 RPM in 10 seconds, I have made 150 revolutions.

[00:14:03]So four is going to be the correct answer.

[00:14:07]Question number four. The sum of kinetic energy and potential energy of a simple pendulum bulb is 0.02 Jew. The speed of the simple pendulum ball at the equilibrium position is approximately consider mass of the ball equal 20 g.

[00:14:29]The options are 2 m/s, 0.2 m/s, 14.1 m/s, 1.41 m/ second.

[00:14:40]Let's consider a simple pendulum here.

[00:14:45]This is its mean position which I'm going to consider it as our equilibrium position.

[00:14:53]These are the extreme position.

[00:14:56]Now we want to find the speed at this mean position.

[00:15:03]So to approach this one important thing I know that at mid position my potential energy is zero.

[00:15:16]So to approach this question as per question the kinetic energy plus potential energy is going to be equal to 0.02 0 2 Jewles.

[00:15:30]My mass of the bulb m is going to be equal to 20 g. I'll convert it into SI unit. So m is going to be equal to 220 /,00.02.

[00:15:52]Now at equilibrium u is going to be zero. So therefore K is going to be equal to 0.02 Jew.

[00:16:10]Now I know that my kinetic energy is given by half m v² = 0.02.

[00:16:19]Now I try to keep only v on one side. So v² is going to be equal to 0.02 into 2 / comes down here and substitute the value 0.02.

[00:16:35]So v ² = 2. V is going to be roo<unk> over row 2.

[00:16:44]V the value of roo<unk> / 2 is 1.41. 41 m/ second.

[00:16:53]So the speed of the simple pendula at the equilibrium position is 1.41 m per second. So option four is going to be the correct option.

[00:17:07]Question number five.

[00:17:10]100 closely warm circular coil of radius 5 cm has a magnetic field of 3.14 into 10 ^ -3 tesla at its center. The current flowing through the coil and magnitude of the magnetic moment of this coil are respectively use mu n = 4 pi into 10 ^ - 7 tesla m per the options are this this this let's try to picture the question a circular coil of 100 turns.

[00:17:57]The total number of turns n is going to be 100.

[00:18:02]From the question, we do not know the total length here.

[00:18:10]It looks like a solenoid, but we don't know the length and we don't know the number of turns for unit length.

[00:18:23]So the magnetic field and current formula for a solenoid uses number of turns for unique length which we don't know.

[00:18:35]Therefore we have to take another approach even though it is a solenoid.

[00:18:41]First let us write the given things and take the approach.

[00:18:47]Here number of stones n is 100. The radius is going to be equal to 5 cm.

[00:18:55]Converting it into meter. It's going to be 5 into 10 ^ minus 2 m or 0.05 m.

[00:19:09]Our magnetic field B equals 3.14 into 10 ^ minus 3 TEAL.

[00:19:20]Our mu n is going to be equal to 4 pi into 10 ^ - 7 tesla m per.

[00:19:34]I want to find my current here.

[00:19:40]So I also have the formula magnetic field at the center of a current carrying point which is given given by b = mu n i divided by 2 r.

[00:20:17]Now since I want to find the i, I'll try to keep i on one side. 2 r d / mu n. I substitute the values.

[00:20:30]2 into R is going to be 5 into 10 ^ minus 2 into B is going to be 3.14 into 10 ^ - 3 / M is 4 pi into 10 ^ - 7 T that's E to per I cancel this pi will get cancelled with this into in place of n it's going to be 100 two zeros two zeros cancel out here 5 all five cancel with together with this two. So I'm left with I = 5 by 2 which is going to be 2.5 m a now I know that my magnetic moment is given by n I A. So n is going to be 100.

[00:21:55]I is going to be 2.5.

[00:21:59]A is going to be p<unk> r² into 3.14 into 0.05².

[00:22:12]I calculate this I get I multiply all this I get around 1.96 which is equal to two which is equivalent to 2 ampere m²ared so my values are 2.5 ampere and 2 ampere meter squared. So my correct option is going to be option number three.

[00:22:52]Question number six. A submarine is designed to withstand an absolute pressure of 100 atmospheric pressure.

[00:23:03]How deep can it go below the water surface? Consider the density of water equals 1,000 kg m cube inverse 1 atmospheric pressure equals 1 into 10 ^ 5 pascal and gravitational acceleration g = 10 m/ second squared the option are this so to approach this let's take a water booty Initially the submarine is on the top.

[00:23:41]So the pressure here is going to be P1 initial pressure.

[00:23:48]After some height as it goes down the pressure here is P2.

[00:24:00]We are given the density of this water the acceleration due to gravity. So let's try to write down the given things here. Given P1 initial pressure is going to be equal to we know that atmospheric pressure in air is going to be 1 atm which converted into pascal will be 1 into 10 ^ 5 pascals.

[00:24:30]P2 is going to be equal to 100 atmosphere atmospheric pressure converting it into pascal 1 into 100 into 1 into 10 ^ 5 it's going to be 100 ^ 7 atmospheric pressure our density of water is going to be 1,000 That means 10 ^ 3 kg m inverse square inverse cube g is going to be equal to 10 m/s squared using variation of pressure with the formula final pressure minus initial pressure is going to be row g H. Now we want to find the depth H. So H is going to be equal to row 2 P2 minus P1 divided by row G.

[00:25:48]I put the values here.

[00:25:51]H equals P2 is going to be equal to 10 ^ 7 minus P1 is going to be 10 ^ 5 divided by row is going to be 10 ^ 3 multiplied with 10 10 ^ 5 comma then 100 minus 1 divided by 10 ^ 4 this this cancelled 10 is left here 10 into I minus this I get 99 so it's going to be 990 m so the correct option here is going to be option number two question number seven match list one with list two list one a e= h This formula is seen in planks theory and this formula gives the energy of the quantile of radiations.

[00:27:05]So photon comes under radiation.

[00:27:09]Therefore this matches with these defraction and interference.

[00:27:17]It is the starting of light where two light waves goes and get interfered get redistributed energy. So this will be P will be matched with wave nature of light.

[00:27:40]Lambda equals H by momentum P. This formula is the formula for deep broccoli's wavelength. So it is going to be one. So the last one should be two. So the option that matches A4 A4 we have two options here either one or two or three or four.

[00:28:10]Amad will go with B. B matches with three. B3 B3 B1. So this one is strike off.

[00:28:21]Two possible cases one and two.

[00:28:25]C matches with one. C matches with one.

[00:28:30]This one. So does the option two is going to be the correct answer.

[00:28:40]Question number eight, match list one with list two.

[00:28:47]Young's modulus.

[00:28:50]We know that Young's modus formula is given by Rama number two. Here compressibility is reciprocal or inverse of bulk modulus. So it's going to be three.

[00:29:07]Bulk modulus is four.

[00:29:10]poisons were show it was supposed to be deleted in the course but once we know this three the obvious formula is these so these are the current match we'll try to see the options from here so when I check it here young's modus matches with two compressibility with three bul modus with four poisonous ratio with one option two is going to be the correct option.

[00:29:48]Question number nine.

[00:29:51]Five capacitors of capacitors C1, C2, C3, C4 equals 10 microfarad and C5= 2.5 microfarad are connected as shown along with a battery of 50 volt.

[00:30:08]This is the circuit diagram. the equivalent capacitors and the charges on each capacitor respectively are these are the option.

[00:30:19]Now let's try to solve this.

[00:30:22]So from this cell or battery current will flow from positive to negative from here to here.

[00:30:32]So if current is flowing in this direction the charge will flow from here to here. Let's say the total charge is Q here. After reach in this point, it will split up into two. This will be let's say this is Q1. The charge flowing here is Q1 and the charge flowing here is Q2.

[00:30:53]All of these C1, C2, C3, C4 are going to be getting the same charge because they are connected in series.

[00:31:05]Whereas this will get another charge because it is connected in parallel with the other four capacitors.

[00:31:14]Now to find the equivalent capacitors, let's try to find the total charge net charge of C1, C2, C3 and C4 which are in series.

[00:31:28]So C1, C2, C3 and C4 are in series.

[00:31:42]Using the formula 1x cs = 1x c1 + 1x c2 + 1x c3 + 1x c4 equal 1x cs = 1x 10 + 1x 10 + 1x 10 + 1x 10 1 by CS = 5 divided 4 divided by 10. So CS equals 10 by 4.

[00:32:19]So CS is going to be equal to 2.5 micro FET CS all of these together C1 C2 C3 C4 net is in parallel with C5. So CS and C5 are in parallel. That means using the formula net capacitance is going to be equal to CS + C5 which is going to be 2.5 + 2.5. So it's going to be 5 micro F.

[00:33:07]Now we got our equivalent capacitance.

[00:33:11]Now we want to find the charge Q1 and Q2 for Q1.

[00:33:23]Since it is going through all of these total, we know that C is going to be equal to Q by V.

[00:33:35]So Q1 is going to be equal to C S Q1 is going to all our series. So C S V CS is 2.5 mean volt is 15. So it's going to be 125 nitro colon.

[00:34:00]Similarly for Q2 we find that Q2 is going to be equal to C5 V. C5 is 2.5 into 50. So we get the same answer.

[00:34:18]So according to the option this and these two are same which means all the capacitor the same charge going through them. So when I look at the option option number four is going to be the correct option.

[00:34:39]Question number 10. The amount of work done to raise a mass m from the surface of the earth to a height equal to radius of the earth r will be these are the option let's get the idea here let's say this is the earth with radius r and object is placed here whose mass is n I want to leave it to a height here h whose height is equal to the radius of the earth now and to move up this from here to here the work down will be stored in the form of energy and the energy with respect to height is potential energy. So we know that work done is stored as energy or energy is stored as work done. So work done is going to be equal to energy but energy with respect to height is potential energy. So potential energy I know that my formula of potential energy is given by mg h. Now in place of h it is r. So mgr.

[00:36:02]So mgr is going to be the correct option. So option number two is the correct answer.

[00:36:09]Question number 11. When a ruler falls vertically, five different persons catch it with different reaction times. Then g = 9.8 m/s squared.

[00:36:24]A person A has reaction time 20 seconds.

[00:36:28]Person B has reaction time 22 seconds.

[00:36:31]Person C has reaction time 18 seconds.

[00:36:35]Person D has reaction time 19 seconds.

[00:36:39]Person E has reaction time 21 seconds.

[00:36:43]What is the correct order of the distance traveled by the ruler for each person? These are the option. Now we will try to see which order is correct.

[00:36:58]Now we know that reaction time is given by P = roo<unk> over 2D by G. I take root to this side. T² = 2D by G. Now 2 and G are constant. So I can say that t² is directly proportional to d where d is the distance or height.

[00:37:29]Now in general I can also say that t is directly proportional to d. That means as t increases my distance d also increases. So with that concept, the more time I take, the more distance the ruler falls.

[00:37:52]So I'll choose the highest reaction time which will be in the first place.

[00:38:00]So this is going to be the highest time.

[00:38:02]So the first place, the second place is this. The third place is this.

[00:38:09]The fourth place is this. And the fifth place is this. So the corre correct auto is going to be B.

[00:38:20]We have B is going to be in the first place. We have two choices in the first place. E is going to be in the second place. E E third place A A fourth place C D. Our fourth place is going to be D. So option number four is satisfying our order here. So option number four is going to be the correct answer.

[00:38:54]Question number 12. The power of a crane which leaves a mass of 1,000 kg to a height of 20 m is 10 second is in 10 second is 10 g = 9.8 m/ second squared.

[00:39:12]The options are this. So to find the answer let's write the given things. m = 1,000 kg.

[00:39:27]H = 20 m.

[00:39:30]P = 10 seconds. G = 9.8 m/ second squared.

[00:39:38]Now we want to find the power and we know that power is weight of doing work. So work done divided by time.

[00:39:56]We know that work done is stored as energy or energy is stored as work done in the previous case.

[00:40:08]So whenever high is there the energy concern is potential energy. So work done can be used as potential energy that is mghided by time. So m is going to be 1,000 into g is going to be 9.8 8 into height is going to be 20 divided by time is going to be 10.

[00:40:35]I cancel this. I multiply my numbers into 1,000.

[00:40:46]Now it is in what?

[00:40:49]Now I can change this 1,000 into kilo.

[00:40:52]So 19.6 6 kilo watt. So the correct option is going to be 19.6 kilowatt.

[00:41:04]Question number 14. An AC circuit contains a resistance of 10 ohm, a capacitor of 0.1 micro farad and an inductor of 1 millenry connected in series. The resultance frequency of the circuit is approximately these are the options.

[00:41:27]Let's try to solve it.

[00:41:31]Given R = 1 kilo ohms which is 1 into 10 ^ 3 ohms.

[00:41:47]Capacitance equals 0.1 microfarad = 0.1 into 10 ^ - 6 farad inductance equals 1 m henry equals 1 into 10 ^ -3 farad sorry Henry.

[00:42:13]Now for the resonance frequency in an LCR circuit we know that new not is going to be equal to 1 / 2 pi roo<unk> / lc I put the values of<unk> 2 into 3.14 / lc l is going to be equal to 10 ^ - 3 c is going to be equal to 0.1 into 10 ^ -6.

[00:42:51]Now this when I convert it it's going to be 10 ^ -1. So the combination of all these will give me 1 / multiply these two it's going to be 6.28 28<unk> / 10 ^ - 10 1 / 6.28 into 10 ^ - 5 I divide this I get 1 / 6.28 28 into 10 ^ 5. Taking off the point here I get 100 / 628 into 10 ^ 5 I divide this I get 0 1 5 9 into 10 ^ 5 I shifted the point from here to here so 15.9 into 10 ^ 3 hertz. Now this can be written as kilo.

[00:44:14]So it's going to be 15 9 kilo hertz.

[00:44:22]So the correct option is 15.9 kilo hertz. Question number 15. The figure given below shows a long straight solid wire of circular cross-section of radius A carrying steady current I. The current I is uniformly distributed across its crosssection.

[00:44:45]The plot which correctly represents the variation of magnetic field B with distance R from the axis of the conductor in the region is these are the option. This is the drawing. So to analyze this, let's draw a axis here. This is going to be our axis.

[00:45:09]So as we go from here to here, the distance varies.

[00:45:16]R varies. Now to note here, a current during solid conductor behaves like a magnet. behaves like a magnet. So for a magnet inside the magnet the magnetic field are going to be strong and they are going to be constant or uniform.

[00:45:40]So and the magnetic field of a magnet is given by b = mu by 4 pi 2 m / r cube which means b is directly proportional to 1x r cube or b is direct inversely proportional to r.

[00:46:08]Sorry. B is inversely proportional to R cube or B is in general.

[00:46:16]B is inversely proportional to R.

[00:46:20]So as we have discussed as we go from away from the axis to the surface of the conductor the magnetic field around here in A will be uniform. So this graph from here to A is not uniform.

[00:46:42]Whereas this one is uniform. This one is not uniform.

[00:46:47]This one is not uniform.

[00:46:50]It goes from zero to a goes increasing here. Goes increasing from a indefinitely and then decrease here. It's slightly increase.

[00:47:04]Therefore the first portion while going from here to here the current graph is going to be this one where the magnetic field is uniform. So as I outside the outside the conductor as I increased my r since it is inversely proportional to distance the magnetic field will decrease. So option number two shows the correct graph for this particular question.

[00:47:39]Question number 16. An electric heater supplies heat to a system at a rate of 100 watt. If the system perform work at a rate of 75 jewles per second, then the rate at which internal energy increases will be these are the option.

[00:48:01]So to approach this let's take the given things given heat supply is going to be 100 jewles because it is per second heat use is going to be 75 jewles.

[00:48:23]So the rate at which internal energy increases which means internal energy is going to be given by heat supplied minus heat used is going to be 100 - 75 equals 25 jewles.

[00:49:02]Since it is rate, it is divided by seconds. So, or if it's saying rate, it's going to be 25 JW per second or watt.

[00:49:15]Therefore, the correct option is 25 watt.

[00:49:21]So option number two is would be the correct answer.

[00:49:26]Question number 17. The peak value of an alternating current is 5A and frequency is 60 hertz.

[00:49:38]How long will the current starting from zero take to reach the peak value?

[00:49:44]To approach this, let's take the wave of an alternating current.

[00:49:54]This is time zero. This is time for half cycle. This is for full cycle. Now we call this point as the peak value.

[00:50:04]P value. So at this to reach from here to here the time is going to be t by4 we're going to use this letter. So let's write the given things here. Given I is going to be equal to 5 a new is going to be equal to 60 hertz.

[00:50:31]I know that time period is given by 1 by mu. So t is going to be equal to 1 by 60 seconds.

[00:50:44]Now for take volume that is at 90° our t is going to be equal to t by 4.

[00:50:59]Therefore from this equation t by 4 that means on this right hand side I have to divide 2 4. So 4 into 60. So tx 4 is going to be equal to 1 by 240 seconds.

[00:51:18]So the correct answer is going to be option number two 1 by 240 seconds.

[00:51:27]Question number 18.

[00:51:30]In Young's double sleep experiment using monotromatic light of wavelength lambda, the intensity of light at the point on the string where the path difference is lambda is K units. The intensity of light at a point where the path difference is lambda by 3 will be to solve this question. Let us first write the given things here.

[00:52:05]The intensity of two lights which are monotromatic. That means I1 intensity 1 is going to be equal to intensity 2 equals I. Let's say because they are monotonic they will have same intensity.

[00:52:22]The wavelength of light is lambda. Now we have seen in the question that there are going to be two cases where the path difference is lambda and the path difference is lambda by three.

[00:52:42]So case one in case one the intensity that means the total resultant intensity at that point when the part difference lambda is lambda is J. So let's take I dash equals J units.

[00:53:06]We have path difference okay >> lambda.

[00:53:16]Now for phase difference I have a formula 2 pi by lambda into path difference.

[00:53:31]So phi is going to be equal to 2 lamb 2 2 pi by lambda into lambda because part difference in this case is lambda lambda lambda cancel. So phi is going to be equal to 2 pi. So using the resultant formula of intensity at any point I dash is going to be equal to I1 + I2 + 2<unk> over I1 I2 cos 5.

[00:54:03]I dash is going to be K. In this case I is I + I + 2<unk> over I I cos 5 is 2 pi K = 2 I + 2<unk> / I² cos cos 2 pi value is 1.

[00:54:28]So k = 2 i + 2 i. So K is going to be equal to 4 I. So I is going to be equal to K by 4. We got I to be this.

[00:54:42]Now in the second case, case two, the path difference is going to be equal to lambda by 3. So phase difference is going to be equal to 2 pi by lambda into lambda by 3. This this gets cancelled. So five is going to be equal to 2<unk>i by 3.

[00:55:14]Now using the same formula, I is going to be equal to I dash 1 is going to be equal to I1 + I2 + 2<unk> / I1 I2 cos 5.

[00:55:37]I1 dash equ= I + I + 2<unk> / I I cos 5 is going to be 2<unk>i by 2.

[00:55:51]Now I1 dash is going to be equal to 2 I + 2 I the value of cos 2<unk> by 3 is - 1 by 2.

[00:56:04]So this implies I d1 equals 2 i. This this gets cancelled plus into minus is minus i. So which implies I d 1 equals i.

[00:56:21]I find that the value of i is 3 by 4.

[00:56:29]So the intensity of light at the point where the path difference is 5 by3 is going to be k by 4. So option four is the correct option.

[00:56:43]Question number 19.

[00:56:46]Four statesmen are given a is math number.

[00:56:52]Statement a. The volume of a nucleus is proportional to a ^ 1 by 3.

[00:57:01]Statement B. The volume of a nucleus is proportional to A. The difference in mass of an atom and its nucleus is called the mass defect. The difference in mass of a nucleus and its constituent is called the mass defect. We are supposed to choose the correct answer from this statement. The option are here. Now let's see what statement are true. The volume of a nucleus is proportional to a ^ 1 by 3. This statement is wrong because we know that volume of a nucleus is directly proportional to a atomic mass or mass number.

[00:57:52]So this statement is not true.

[00:57:56]The volume of a nucleus is proportional to a. Now this statement follows the statement we have discussed. So this is true.

[00:58:08]The difference in mass of an atom and its nucleus is called the mass defect.

[00:58:14]Mass defect.

[00:58:16]According to mass defect definition, it is the difference between the nucleus not the atom but the nucleus and its constituent nucleons that is proton and neutron. So atom and its nucleus it does not fit the definition. So this is false.

[00:58:40]The difference in mass of a nucleus and its constituent is called the mass effect. So as we have discussed mass effect is the difference between the nucleus and its constituent proton or proton and neutrons. So this statement is true. So our statement B and D are true but A and C are false. So let's try to see the correct options.

[00:59:10]B and D are true. So B and D are true but A and C are false. So two is going to be the correct answer. Question number 20.

[00:59:23]In interference and defraction the light energy is redistributed.

[00:59:36]If it reduces in one region producing a dark fringe, it increases in another region producing a bright fringe.

[00:59:50]Statement A. As there is no gain or loss of energy, this phenomena are consistent with the principle of conservation of energy. Statement B. Defraction and interference are characteristic XB exhibit that only by light waves.

[01:00:13]The options are A is false but B is true. A is true but B is false. A is true and B is also true. Both A and B are false.

[01:00:27]In this case as clearly mentioned in the first sentence the light energy are redistributed in interference and dis and defraction which means the energy of two or more lights gets redistributed. There is no addition or loss of energy. So the statement A there is no loss in gain of energy. So it follows the principle of conservation of energy. Statement A is true.

[01:01:06]Let's talk about statement B. Defraction and interference are characteristics exhibited only by light wave.

[01:01:17]We can see interference even in radio waves or sound waves. For example, in radio waves, we can hear the static noise when two frequencies get interfere with one another. So it defraction and interference does not only take place in light waves. It can also be seen in radio waves and sound waves. So this statement is false. So statement A is correct but B is wrong.

[01:01:50]False. So option number two is going to be the correct option where A is true but B is false.