Did NECO 2026 Physics Practical Question 3 Just Leak?

[00:00:02]Hello guys. This is Prime Concepts.

[00:00:05]You're welcome once again to my channel.

[00:00:07]Thank you for always connecting with Prime Concepts. Now, just like we did in our WAEC Practical Physics 2026 preparation, we were able to predict the questions for WAEC and then it came out very much similar to what we predicted.

[00:00:24]Now, NECO is just by the corner in few weeks time. We're talking about NECO 2026 Practical Physics. And we want to do just the same thing we have done for WAEC and even this time do it much better, right? So, this time around, we want to analyze NECO 2026 Practical Physics [clears throat] for question number three, which is the question under electricity.

[00:00:49]So, I've been able to look at um the trend in NECO, look at the apparatus that are required, and then I've been able to come up with a question that you're likely to meet in your NECO 2026 um examination that'll be coming up very soon. One of the things I want you to do is to make sure you are subscribed to this channel because a lot will be unraveled, a lot of secrets will be revealed. I'll be showing you secrets, just like I showed you in WAEC. And one of the things you need to know is the end point of your Practical Physics for electricity. What is expected of you at the end of the experiment? When you finish plotting the graph, just like I said, how do you know that your answer is correct? I told this same thing to my WAEC students and most of them came back calling me, reaching out to me, saying, "Prime Concepts, this is what happened in our WAEC and the same slope you told us is what we obtained in our exam." And I showed them why what they got was perfect. So, same thing is going to happen because at the end of the day, what is very much important is for you to be able to plot your graph and get your slope. And the accuracy accuracy of your slope is going to be dependent on the accuracy of your readings. So, what I'm going to do in this video is I'm going to show you what no one else would show you. And what is that concept? Like you can see, I have the questions on the board, the possible questions on the board. And I'm going to show you how you can carry out this experiment without even touching any of the apparatuses. And in my subsequent [clears throat] videos, I will carry out the experiment and you will see I will be obtaining same result. Let me even tell you that what we're going to obtain here will be more accurate than anybody can obtain. All right? So, do well to stick with me till the end of this video so that you can get full benefit from this video. So, let's look at what we have.

[00:02:45]Now, we have electricity problem as predicted for NECO 2026. And this is the circuit arrangement that you should be expecting. This is your [clears throat] EMF from your dry cell or your lead accumulator. Now, anyone your school has, but in this case I'll be assuming a dry cell. Now, you have your key, which stands as your switch. You have your ammeter. They gave us the range of our ammeter from zero to two amperes. So, it tells us that our readings our current readings are going to lie between zero and two amperes. So, there's already a restriction. Then we have this is our resistance box, which serves as our variable resistor. So, it means we're going to vary the resistance to measure current and even measure voltage. Now, they said you are provided with an ammeter, a voltmeter do not included in this circuit diagram, but you would see that at the end of the day, you can include your voltmeter here.

[00:03:49]But, NECO is fond of and WAEC they are of not putting it in the circuit diagram so that sometimes you may be confused, right? But then you want to place it, you will place it around here.

[00:04:02]So you place it around your resistance box, right? Now, so you are provided with an ammeter, a voltmeter, a resistance box, connecting wires, dry cells, which is [clears throat] this, and other necessary materials.

[00:04:20]Now, they said the first procedure, connect the circuit as shown in the circuit diagram above. So, we need to connect as shown, which is very easy.

[00:04:31]You have your battery, you link from one side of your battery to your to your resistance box. Then you link from the other end of your resistance box to your ammeter, from the other end of your ammeter to your key. That is just what you're going to do, but remember, the secret I want to show you here is such that if you have attended a school where maybe you've not been opportune to carry out this practical through your stay in your school, then and you are so scared, what do you do?

[00:05:00]How do you even manipulate these things?

[00:05:03]I'm teaching you the secret that helps you such that you would not need to even make this circuit arrangement, you'll be able to get your table of values without assuming values because in NECO, it's necessary not to assume values. What is NECO marking? NECO is marking your values. So if your values are not accurate, you're [clears throat] already losing marks. But they're marking your values, they're marking the trend in your values, whether they are decreasing as supposed or increasing as supposed or oscillating as supposed. So NECO is marking your values, they are marking the trend in your value. So don't assume. I'll show you how to get it without assuming and without even performing the experiment.

[00:05:47]So the first procedure, procedure one, says "Connect the circuit as above in the circuit diagram." And procedure two, "With the key with the [clears throat] key open, record and record the open circuit voltage V not of the battery. So, when the key is open, when the key is open, it simply means that your battery is not supplying current. So, it means that when your key is open, you just carry your voltmeter, and this is your battery.

[00:06:22]This is your battery. So, when your key is open, you carry your voltmeter, connect it this [clears throat] way.

[00:06:28]Connect it this way. So, once you measure that, that is very important.

[00:06:33]See what NECO likes to do. Now, which most students don't actually understand.

[00:06:39]You would notice that when NECO or WAEC tells you to measure a particular quantity and record it, it is because that quantity you have measured is what they are going to use to judge you.

[00:06:50]Well, a lot of you don't know. You just measure. Some of you don't even measure and carelessly write anything you're thinking of. Now, let me tell you. They said we should measure the open circuit voltage V not and record it, right? Now, the for this particular experiment, we are using two We are using two cells like this.

[00:07:16]We are using two cells. And our assumed values for them is going to be Our recorded value is we're going to assume this as 2.9 V.

[00:07:34]We're going to assume the value what?

[00:07:36]2.9, which is very correct. So, on your exam day, you use this value as your measured value, you'll be very correct.

[00:07:45]So, don't worry about it. You can use 2.9, you can use 2.8, you can even use 2.7. These are values that are okay.

[00:07:53]But, I'm going to be using 2.1 9, and I'll be using that to make my calculation. So, this is the value you have measured from question number two, right? Yes, and I will be showing you how to record it to create your table of values. So, because I've been able to read here, I'm going to rub this and begin to record all the things that I'll be needing.

[00:08:16]So, and let us create our table how it is going to be on that day. So, but let's keep reading. So, they said question number three, "Close the key." This time around, you are now going to close the key. Close the key means when you close it, current begins to flow. So, close the key, "select a resistance R equals 0." So, it means from your resistance box, your resistance box, you're going to be having making sure that the value of resistance you have is 2 ohms. So, select a resistance of 2 ohms on the resistance box.

[00:09:00]"Read and record the current I on the ammeter." So, when you do that, you have opened 2 ohms, you're going to take the ammeter reading, and then corresponding terminal PD potential difference on the voltmeter. So, you're going to record your current, you're going to record your voltage. So, those are the two things you are going to measure when you have a resistance of what? 2 ohms. So, let us create our table. So, in our [clears throat] table, we're going to have the space for our serial number.

[00:09:33]We're going to have our resistance. That is what we are varying. Remember the resistance is 2.0 ohms. So, it means we'll be varying the resistance through the resistance box. So, and the unit is ohms.

[00:09:47]So, we have this. Again, they said we should measure the current. So, we have our current in ampere.

[00:09:54]Again, they said we should measure the voltage.

[00:09:57]V Now, for students to have some other quantities to deal with.

[00:10:02]So, we have this. So, I have 1 [snorts] 2 3 4 5. So, I'll be having five different values for this. Now, remember they told you earlier told you to measure this. So, what you do is you come at the top of your table. That is the best place to write it. V naught equals 2.90 because this is what they will judge you with.

[00:10:27]So, make sure you write it at the top of your table.

[00:10:31]So, you have created your table. So, the first resistance is two. You don't need to write ohms again because it's already written here. Now, they said repeat the procedure for four other values of R equals 4 ohms, 6 ohms, 8 ohms, and what? 10 ohms. So, the varying resistance is 4 >> [laughter] >> 6 8 and 10. So, these are the varying resistance values we have. So, they said in each case read and record the values of I and V. So, that is why we have these columns for I and V. Evaluate I inverse and V inverse. So, we have two other things to be present on our table.

[00:11:18]So, we have I inverse.

[00:11:23]We have this and we need to create a column for V inverse. So, because of space, I'll leave that for now. Let's work with this and later I'm going to create that. So, evaluate I inverse which is this and then V inverse. We need to create another column for that.

[00:11:37]And plot a graph of R against I inverse.

[00:11:43]So, take note of that. You'll be plotting R against I inverse. So, they said determine the slope S and intercept of on the vertical axis. So, what am I going to do? I'm going to show you the secret on how you can determine this table of values without assuming values and without performing the experiment.

[00:12:06]So, move with me. At this point, if you are yet to subscribe to my channel, please do well to hit the subscribe button because before your practical physics in WAEC, I'll be dropping a lot of secrets that will be saving a lot of students in the exam. A lot of students have testified for the WAEC, the JAM. So, do well to follow up with our channel.

[00:12:28]Always drop a comment. If you have a question in any part of the video, do well to ask. If um you have friends that are also writing this, do well to share with them. Tell them it is Prime Concepts. So, let's Let me rub this space so I can use it.

[00:12:50]So, I have >> [snorts] >> this now.

[00:12:55]Remember, they said I should also create a space for V inverse.

[00:13:00]So, I have this. So, this is my complete table. Now, let's fill it together. To fill this, I just need two formulas.

[00:13:09]What are the two formulas I need? I need first to know that I is equal to E or what you're going to call V not over R plus small R. Now, in this formula, what does E represent? E is actually your V not, which is actually the EMF >> [snorts] >> of your cell. So, that is E. Then, R is this external resistance that you're varying. Then, small R is the internal resistance of your cell. So, for a dry cell, for a dry cell, the internal resistance is usually between 0 0.1 to around 0.5. That is the range of values for an internal resistance of a dry cell, right? Of 1.5 V.

[00:14:03]So, you have We're going to assume our internal resistance to be around 0.3 ohms. So, we're going to make that assumption, which is very safe. It's a very safe assumption. So, then, we have another formula we would be needing, which is the formula for V.

[00:14:22]We're going to use to get the V is equal to I * R. So, with these two formulas, we can get everything we need on this table. So, let's start very quickly. So, for R equals 2 ohms, that is to say, for this first value, I'm going to make my calculations. So, I have that I is going to be E, which is 2.9 / 2, which is R, + 0.3. So, if I run this calculation, I'm going to have 2.9 / 2.3.

[00:14:57]So, this [clears throat] is going to give me 1 This is going to give me 1.26.

[00:15:05]So, this is what I have. Now, if I get these corresponding values, 1 / 1.2 6. Remember, this should be two place of decimal or at least one place of decimal. So, but let's maintain two.

[00:15:19]Then, this I inverse is a calculated You're calculating this from this. So, this is going to be a minimum of three decimal place. So, what I have is 0.

[00:15:30]79 4. So, that is what I have there. What about my V? I'm going to use this formula. V becomes I * R. So, what is I?

[00:15:41]I got I as 1.26.

[00:15:44]So, I have 1.26 * R, which is 2. So, this will give me 1.26 * 2.

[00:15:54]So, this will give me 2.

[00:15:58]52. So, I have 2.52 here. And if I take the inverse very quickly, 1 / 2.52, this will give me 0.3 9 7. So, I'm going to do the same thing for others. So, this time I'm going to change R to 4.

[00:16:25]So, this time I'll be working for R equals what? 4. So, I'm going to change R into 4. So, this is going to be 4.

[00:16:32]This is going to be 4. So, let's do that calculation again. So, 2.9 / 4.3.

[00:16:40]So, this is going to give me I as 0.67.

[00:16:45]>> [clears throat] >> So, let me write it. 0.67.

[00:16:49]So, if I quickly get the inverse, 1 / 0.67.

[00:16:55]So, this will give me 1.

[00:16:59]493.

[00:17:01][clears throat] So, if I get this value, 1.

[00:17:05]26 * 4.

[00:17:08]So, this will give me This will give me 5.04.

[00:17:15]Let's Let me recalculate.

[00:17:18]Okay, so there's an mistake here.

[00:17:20]So >> [clears throat] >> So this is going to be 0.67 * 4.

[00:17:28]2.67 * 4. Make sure you run these calculations with me to help you master it.

[00:17:35]2.68 So I have 2.68. So if I get this inverse, 1 / 2.68 >> [clears throat] >> I would have 0.373.

[00:17:52]373.

[00:17:54]I'll have this. So I'll run for six. So it means I need to change this to six.

[00:18:01]Six.

[00:18:02]I need to do this.

[00:18:05]So this time I would have This is going to be for six ohm. Six. So if I do this, I have 2.9 / 6. points.3 >> [clears throat] >> So this is going to give me 0.46 46 [snorts] So 0.46 * 6. What is this going to give me?

[00:18:30].46 * 6 is going to give me 2.76. So recording my values, I have 0.46.

[00:18:41]I have 2.76.

[00:18:44]So to get the inverse, I have 1 /.46 is going to be 2.17 4.

[00:18:57]And the next is 1 / 2.76 which is going to be 0.36 2.

[00:19:08]So the next I'm going to do for eight.

[00:19:10]I'm almost done. I just want to go through everything >> [clears throat] >> since you're learning. Otherwise, I would just write the answers. So, let's go through them together so you would master it. So, the next is for 8 ohms.

[00:19:22]So, 8 going to have 2.9 divided by 8.3.

[00:19:30]So, this is going to be 0.

[00:19:33]35.

[00:19:34]0.35 * 8. So, let's see what we have.

[00:19:39].35 * 8 going to be 2.8.

[00:19:45]So, I'll record my values. [snorts] 0.35 is 2.80.

[00:19:53]So, let's get the inverse. 1 /.35 So, this is going to give me 2.857.

[00:20:04]Yes. The next one is 1 / by divided by 2.8.

[00:20:14]So, this is going to give me 0.

[00:20:16]35 7. And finally finally the last one is when R is 10.

[00:20:27]So, when R is 10 So, I'm going to have for 10 ohms. So, I have this.

[00:20:32]10 times So, I have 2.9 divided by 10.3.

[00:20:42]So, this is going to give me 0.

[00:20:46]28 again.

[00:20:49]*.28. [snorts] So, this is going to give me um 2.8.

[00:20:56]So, if I record, I would have It's going to give me 0.28.

[00:21:03]It's going to give me 2.8.

[00:21:06]0 and this is going to give me Okay.

[00:21:13]1 / 0.28.

[00:21:16]So, this is going to give me 3.

[00:21:19]5 71. This is going to give me 0.357.

[00:21:27]So, this is what my table of value would look like for NECO 2026, right? And this is very beautiful. And they want us to plot a graph. And let's see. I'm going to plot the graph. So, watch. I believe I can rub this now.

[00:21:44]Now, they want us to plot a graph. They said plot a graph of R against I inverse. So, this is what they want you to plot. Now, like I told you, without plotting any graph, you can always tell what your answer would be.

[00:22:00]So, let me help you understand. Since you want to plot R against I inverse, it means you'll be plotting R on which axis? You're plotting R on the Y axis, and then you'll be plotting I inverse on the what? X axis. That is what the concept is. Now, let's return to this formula and see and try to make R the subject since we're plotting R on the Y axis. So, from this I have that I equals E over R plus R.

[00:22:31]If I cross multiply, I have that E is going to be I into R plus R. Can you see this? Yes. So, E is equal to I R plus what?

[00:22:45]Okay, let's go this way.

[00:22:50]Let's go this way. Now, let's divide through by I.

[00:22:53]>> [clears throat] >> So, I'm going to have E divided by I equals R plus R. I hope you believe that this is true. Yes, so if I make R, capital R the subject, I will have that capital R is going to be is going to be E * 1 over I - R. So, this is what I'm going to have, right? Or I can still write it this way. R equals E * Remember, 1 over I is the same thing as I inverse and minus R. So, this formula is very important to us. Now, if you compare this to the equation of a straight line, which says that Y equals MX + C. Remember, they asked you to plot a graph of R against I inverse, and two things they want you to obtain is your slope.

[00:23:51]They want you to obtain your slope and also obtain your what? Your intercept.

[00:23:56]So, by comparing this under this experiment, your slope, remember M is your slope, your slope represents what?

[00:24:04]The EMF of that cell. And then your intercept is the negative of the internal resistance. So, it means when you plot the graph of R against I inverse, your slope is expected to be around 2.9. So, if you get a slope of 2.9, you are perfect. If you get a slope of 2.8, perfect. You get a slope of 2.7, perfect. You get a slope of 2.6, perfect. You get a slope of 2.5, perfect. You get a slope of 3.0, perfect. So, if you get values around 2.5 down to let's say even 3.4, you get values around this, then your slope is perfect. It's okay.

[00:24:49]It's okay because these values will approximate to three. So, it's okay. So, when you plot this graph, I want you to plot it, come back to this video, drop in the comment section, tell me what you got.

[00:25:01]If you follow the concept I've explained in graph plotting, trust me, you'll be able to get it. But, I'm going to plot this graph in my next video, and I would like [clears throat] you to watch it.

[00:25:10]But, before you watch it, I would want you to plot this. Tell me your own slope. I want the best slope. I'm going to see what I'm going to do. Maybe I'll do a giveaway in my next video. But, I want you to plot it. Drop the answer to the slope you obtained in the comment section. So, we should be around this.

[00:25:26]What about to the intercept? Your intercept Your intercept is expected to be around negative of 0.3. The intercept should be around this. So, if you get your intercept, first of all, must be negative.

[00:25:43]>> [clears throat] >> It will be what? Negative. So, if you get something around 0.3, 0. Mm.

[00:25:50]4 is okay. 0.5 is okay. 0.2, 0.1 is okay. So, this is how that graph would look. Let me show you even before you start plotting. This is how that graph would look.

[00:26:06]>> [snorts] >> So, the graph is going to look this way.

[00:26:11]It's going to look this way.

[00:26:13]So, This is how that graph is going to be.

[00:26:19]Like this. So, it means that when you are plotting this graph, make sure that you create a space on the negative Y axis because you're going to have the graph cut through your negative Y axis.

[00:26:30]This is going to be your R axis in ohms, and this is going to be your what?

[00:26:35]I inverse axis in inverse of ampere. So, this is how your graph is going to be.

[00:26:41]Take note. It would cut through this axis. So, it means if the concept is clear to you, before you even start plotting, you should have created the space under. So, if this video is very helpful to you, I would like you to subscribe to this channel if you are yet to subscribe. Remember we have question number one in MECO, which is on mechanics. I'll be solving it and I'll be showing you how you can obtain it without performing performing the experiment just like this. You have question number two, which is under rectangular prism optics. I'll be showing you how to draw your outline.

[00:27:15]Some of you think you can only produce your outline by viewing. I'll show you how to view and I'll also show you how to produce that outline even without viewing the most perfect way. And then electricity, I'll give you some other variations of this electricity. So do well to stick with me in this channel.

[00:27:33]Hit the subscribe button, hit the like button, drop a comment, and share with your friends. Thank you. I remain Frank Concept.