00:02 Good day, class.

00:12 My name is Eme Nnamdi John.

00:14 I'll be taking your physics with a topic, Magnetic Field.

00:18 Today, at the end of this lesson,

00:21 Lenas must be able to explain the concept of magnetic field,

00:25 least type of magnets.

00:27 Explain the concept of demagnetization and how to make a magnet.

00:32 Now, first, what is magnet?

00:37 Magnet or magnetization or magnetic field is a region

00:42 where forces or magnetic forces are being experienced.

00:46 Now, under this magnet, we have this as a magnet,

00:51 as a bar magnet.

00:53 We call this a bar magnet,

00:55 which have the North Seeking Pool and the South Seeking Pool.

00:59 Now, in this pool, we have this, like this,

01:03 we have this, like this.

01:06 It simply means that the forces

01:10 leaves the North Pool and comes into the South Pool.

01:17 That is,

01:22 these are called the magnetic flocks.

01:25 We have these,

01:30 magnetic flocks.

01:37 Now, these are areas of the North Seeking Pool

01:42 and the South Seeking Pool.

01:44 It simply means that the flocks are leaving

01:47 from the North Pool and they're entering into the South Pool.

01:51 It simply means that you also have it to be like this,

01:54 North, South,

01:58 you have it like this.

02:03 That is, it's moving from here to here.

02:14 Now, it's moving from the North side to the South side.

02:19 That means it's been terminating into this place.

02:24 Now, coming off from this place,

02:26 that is how it flows.

02:29 That is how the region flows.

02:31 The flocks flows from the North side to the South side.

02:36 Now, if we look at these,

02:40 these ones are the imaginary lines.

02:47 These are the imaginary lines,

02:49 but the lines must not meet.

02:52 The line must not meet.

02:56 The line must not meet.

03:00 It's going out, it's going out.

03:05 It's coming in into this place.

03:07 It's also coming in into this place.

03:09 That is how it is being given out.

03:11 Going out, usually called conventional,

03:14 on that point, we say conventional currents.

03:16 Now, this is moving like this into this place

03:19 and it's coming from the North side to the South pool.

03:23 Now, the pattern we are giving,

03:27 we are giving types of ways of this.

03:31 We have this, let's see.

03:33 This is called a bar magnet.

03:38 We have a light pool, we have North pool.

03:44 Let's find some, we have a light pool.

03:49 That means this can attract this.

03:53 There will be an attraction between these two.

03:55 That is, this can flow like this.

03:58 There's an attraction, light pools.

04:02 That is, on light pools, we have this.

04:04 It's entry like this.

04:10 When we talk about on light pools,

04:11 that means North and South, these are on light pools.

04:13 There always would be an attraction between these two

04:17 and an attraction would take place.

04:18 Now, when we not talk about the North and the North,

04:25 there will not be any attraction reason

04:30 because there will be a repulsion.

04:32 Now, this is going out and also this is going out.

04:36 Let's look at this very well.

04:39 Let me draw it very well.

04:44 Now, in the sense of this, we have North, we have North.

04:50 Now, North is going out.

04:54 Now, because of this, this is going out

05:02 and also this is going out.

05:04 There will be a repulsion at this place.

05:09 That means it will flow like this.

05:12 Well, I'm drawing this one

05:14 because when it comes to this place,

05:16 they will terminate at this place.

05:17 There will not be any flow that will move through that.

05:19 Then, the diagram will look like this.

05:21 Like this, look at this.

05:29 We have North.

05:31 We have North.

05:33 There always be this repulsion sign here.

05:38 Because this is going out.

05:40 This is also going out.

05:41 This is also going out.

05:43 This is also going out.

05:44 And there will be a repulsion in this place,

05:48 whereby the tool cannot be able to attract itself.

05:52 Likewise, the south pole,

05:55 the south seeking pole and the south seeking pole.

05:58 The center is applicable because it's coming in.

06:02 The flocks are coming in.

06:07 The flocks are coming in.

06:11 Now, there will be a repulsion also.

06:20 There will be a repulsion.

06:22 North, North, North, they will repair.

06:25 South, South, they will repair both.

06:26 Well, you have the North and the South.

06:28 There's always what an attraction.

06:35 Okay, let's talk about the magnetic feed around

06:42 a straight conductor carrying currents.

06:44 No.

06:47 Now, we're using our right hand grip to explain this.

06:53 Now, if you look at my hand, look at this.

06:56 If I have this to be like this,

06:58 I'm trying to explain right hand grip,

07:01 which is given to be like this.

07:03 Now, from this place, we can also talk about

07:07 Maxwell College Group Rule.

07:09 State the tips, travel along the direction of currents.

07:12 The direction of the rotation of the coach

07:14 will give the direction of the magnetic feed

07:17 or the magnetic line of flocks.

07:20 Now, what are we trying to see if we are to give on this?

07:24 Look at this.

07:27 Just, for instance, we have this.

07:34 Then, we can have this current to be like this.

07:49 Now, it simply means that the current flows like this.

07:58 That is what the coach trying to tell us.

08:00 When you grip the current like this,

08:02 the current flows around each like this.

08:08 That is, it's given on the board.

08:11 Current flows.

08:14 There's always a flow of the currents.

08:18 There's always a flow of the currents.

08:20 And this current will be flowing continuously like that.

08:27 Okay, we'll talk about magnetic feed around a solenoid.

08:32 Now, a solenoid is along a cylinder

08:38 of a wire who stands usually.

08:41 Now, for this, we have a coil.

08:45 Let's say this is given to rows.

08:54 Sorry.

09:00 Look at this.

09:15 Now, from this side, you can see that a current flows like this.

09:20 Look at this.

09:23 From this, this flows like this.

09:25 See, this, from here, you see that the current is flowing like this.

09:32 You can see the current flowing around this bar magnet.

09:39 This nodes pull.

09:41 From here, you can see that the currents are flowing from this place.

09:47 Look at this.

09:50 That is how it should be going.

09:52 Now, it's rotating from this place, from the north side,

09:55 terminated to the south side.

09:59 That means we, like we said before, that these will be flowing from here.

10:03 The flux are flowing from here.

10:05 That is where we have these to be like this.

10:08 And we'll trace it.

10:10 It's moving through the solenoid of the bar magnets.

10:13 That is how it should be flowing and be flowing continuously.

10:22 Alright, we would talk about magnets.

10:25 We are told that magnets is anything that can magnetize.

10:30 Anything that can magnetize, as we are called, what is a magnet.

10:34 Anything that can magnetize, any material that can attract anything is called a magnet.

10:40 I will say, say, a magnet can be defined.

10:42 Any material that can attract substance such as ion, steel, cobat, nickel, or etc.

10:48 We have many of them, many.

10:53 We have type of magnets.

10:55 We have the natural magnets, and we have the artificial magnets.

10:59 Now, what are the natural magnets?

11:02 These are magnets that are found in the edge crust.

11:05 These ones are natural.

11:07 They are not being done by anybody.

11:09 They are natural.

11:10 Why the artificial magnets are those that are being made by man.

11:13 Man can make magnets.

11:15 Anybody can make magnets.

11:17 It can be done in the laboratory.

11:20 Anywhere magnets can be made.

11:22 Now, what's the difference between ion and steel?

11:26 One, ion can easily magnetize.

11:30 But it will not long.

11:34 It will not take time to magnetize itself.

11:38 Why is steel takes time to attract both?

11:42 Take longer time to magnetize itself.

11:46 Okay, this is soft ion.

11:50 Now, method of making magnets.

11:53 There are four methods of making magnets.

11:55 We have one by LHK method.

11:57 LHK method, two by LHK method.

12:03 Okay, let me explain the LHK method.

12:05 Now, we have these, which are direct currents.

12:11 LHK methods can be used also with direct currents.

12:14 We have these.

12:24 Let's say these are bar magnets.

12:28 Let's say these are bar magnets.

12:33 Which is solenoid in it.

12:36 Current flows like this.

12:39 With the solenoid in it, we can produce a bar magnets.

12:48 This is a generator.

12:50 It flows like this.

12:53 We have this.

12:55 We have this.

12:56 Because it's flowing like this.

12:58 And this is going and is flowing to this place.

13:07 With direct currents.

13:10 We can use direct currents to produce or to make magnets using LHK method.

13:17 Which is solenoid.

13:19 We have other ones.

13:20 We have single torch.

13:21 Now, from here, from the single torch, we have such a ten like this.

13:28 We have the notes, or let's say A, and we have B.

13:32 It does a single torch, where you strike once, it can be produced.

13:40 Using a bar magnet, the side of H, which is what the notes,

13:44 I will help with this out.

13:46 Now, these can flow like this.

13:50 It flows like this.

13:52 That is how it flows.

13:55 Like this, or it can flow like this also.

13:59 It flows like this.

14:02 Let me draw it very well.

14:05 So, how space to see it?

14:10 We have this.

14:15 Let's say A and B.

14:18 We have this.

14:23 This out and this is not.

14:25 Now, it flows like this.

14:31 And by Soudouin, we produce this.

14:36 Flowing like this, moves like that.

14:40 Now, we can produce this by single torch.

14:43 We have what we call the double torch.

14:45 A double torch.

14:47 As you can see from the slide we have, that this is given already.

14:52 It's opposite bar magnets.

14:56 We have this.

14:58 Let's say, first bar magnets and the second one.

15:03 They are opposite to each other.

15:05 We have the notes.

15:06 We have the sounds.

15:08 We have the notes.

15:10 We have the sounds.

15:12 Now, it simply means this can flow.

15:22 There's always, that means from here to this, please.

15:38 Like this.

15:43 The flux flows like this.

15:47 Now, we have this.

15:54 That means the flux like this also.

15:58 These are the ways of producing a magnet.

16:02 Now, let us see how we can demagnetize a magnet.

16:07 Now, once again demagnetize to destroy a magnet.

16:11 Now, what it means to demagnetize means to destroy a magnet.

16:14 Now, one of the ways to destroy a magnet is biological method also.

16:19 The first one, when we have to make a magnet, we use what we call the DC,

16:25 which is the direct current to make the magnet.

16:30 But now, we are going to use the AC to destroy the magnet.

16:33 In the sense that we have the same diagram but using an AC, which is an alternate current,

16:38 to destroy the magnet.

16:40 Like this.

16:46 These are AC.

16:48 We can use it to destroy the magnets.

16:54 It also, it's solenoid also, giving to Ross.

17:02 An AC, that is only thing that can be added to, we need to destroy the magnets.

17:09 Using an AC, we can destroy the magnets.

17:16 Using an AC, these magnets can be destroyed.

17:20 Now, we also have heating to red hordes.

17:23 Now, when we heat a magnet to red hordes, don't like the blacksmiths.

17:26 When we put a magnet into a fire, it will demagnetize its attraction or demagnetize its magnetic feed in heat.

17:35 Also, when we, when we, hammer it at the, not side, when we hammer it, it will also demagnetize its also.

17:43 And when we hammer it, also, we can also destroy the magnets.

17:50 Like you have this, which has been spent to Ross.

17:53 Okay, what are the properties of magnets?

17:57 Properties of magnets.

18:01 Now, one of the properties of magnet is suspension.

18:03 Now, how can we be able to get suspension?

18:06 Now, when we have a not pull, we have a not pull, let's say this is magnets.

18:18 Let's see, we have this, which is magnets being, this is how the magnet will be suspended.

18:29 We have the not and the salt, whereby the not, the not pull will be putting its head at the edge.

18:43 Why the salt, we, we go up.

18:46 The not, we calm down to the edge. Why the salt, we go up.

18:50 Like we said, it's suspended by magnets.

18:53 We always lie in the not south direction, which is this, not south direction.

18:58 The end point of the not is called the not seeking pull.

19:01 Why this side is called the south pole, it's called the south seeking pull.

19:07 We have ripple concepts.

19:10 Ripple concept, this is the concept which explained its practically that magnets can never be destroyed.

19:17 No matter how you want to do it, it can never be destroyed from attracting itself.

19:22 If a magnet is given to Ross, like this, look at this.

19:27 We have this magnet.

19:29 No matter how you want to break a magnet, it will see attract.

19:34 Now, this is a not pull and this is such pull.

19:37 If I destroy this magnet, yeah, I will have another not pull.

19:48 I will have another not pull like this, like this.

19:54 And this, that was being broken, and also this, also.

20:00 It will form another not a south seeking pull, which is another south.

20:06 This will form nots and this will form south.

20:09 If I should break this one again, it will form another nots.

20:21 There is a concept of this, ripple concept.

20:24 No matter how you are breaking a magnet, it will form the not pull and also the south pole.

20:29 Like this, we have the nots and the south, the nots and the south.

20:34 Likewise, this one, when we break this one from this place, we have this.

20:44 We have this like this.

20:50 We have nots, south, nots, south.

20:54 That is one of the concepts of ripple concept.

20:59 If you break a magnet, no matter how you break a magnet, it will produce what they not side and the south side.

21:06 No matter how you break the other ones, you will see how nots and south.

21:12 We have the polarity concept.

21:15 Now, let me understand the polarity concept.

21:19 Polarity concept explained that when a bar magnet is given to us, a bar magnet is given to us.

21:28 Let's say nots and south.

21:30 And a powder is being poured on the bar magnet.

21:35 The power of it will be formed at this place.

21:41 This place, this is where the power will form.

21:46 This means the power will shift to the north seeking pole and also what the south seeking pole, just like this.

21:55 This is where the powder will form itself.

21:58 The powder will be poured at the bar magnet.

22:00 It will go at the side, the seeking pole, which is what the north seeking pole and south seeking pole.

22:06 This is how it will look like.

22:08 We said when some iron powder up, as pink on the bar magnet, most of the powder will clean to the end of the bar magnet.

22:17 This is how it will look like.

22:18 It will clean to the end of the bar magnet, which is what the north side and the south side.

22:26 Now, we talk about induced magnetism.

22:29 No, let me explain the induced magnetism.

22:34 Now, this is done whereby a magnet, a bar magnet, this is a bar magnet.

22:42 We have north and we have south.

22:45 Now, we have a pin whereby a little pin, which is this, can attract another pin.

22:57 And this pin can attract another pin.

23:04 And this pin can attract another pin.

23:10 And this one can attract another pin.

23:14 Now, one of the things about this is that the pin at this side has less power to attract very well,

23:22 unlike this one that is close to the bar magnet.

23:26 Now, like we said, when a pin is placed below a magnet, it becomes attached.

23:33 Like I drew here, it becomes attached.

23:35 This means it can attract other pins, giving it right to the magnet chain.

23:40 This is a chain giving to rows.

23:42 This is a magnet chain giving to rows.

23:45 Now, I saw this one at this place.

23:49 The force is very weak because no matter if the pin, the chain is wrong.

23:56 The one at the end, you have less power to attract.

24:06 All right, let's talk about concepts of magnetic force.

24:10 We said, is the region where magnetic forces has been experienced?

24:14 Like we rightfully discussed, we talk about the way by light poles, light poles repair.

24:23 Look at this, knots and knots.

24:27 There is always a repulsion.

24:30 There's always a repulsion.

24:33 And we have this, south, south.

24:38 There's always also a repulsion.

24:41 This is gray knots, this is gray knots, this is gray knots, this is gray knots.

24:47 There's always a repulsion.

24:49 We have this also coming in, coming in.

24:53 We have this also coming in.

24:59 There's always a repulsion.

25:01 But when we have a bar magnet towards north and south,

25:07 there's always an attraction between them.

25:12 There's always an attraction between this pool.

25:17 Let's see.

25:19 There's an attraction between these pools.

25:24 Which you have to be like this, not what we've explained before.

25:29 But let's make, we have it to be like this.

25:33 You can see there's an attraction between them.

25:38 There's an attraction between these magnets.

25:44 There's an attraction.

25:47 There's an attraction.

25:49 While the other ones are repaired.

25:53 Because we had told that towards light poles repair, why on light poles are trucks.

26:01 Now let's talk about magnetic force on the moving charge in magnetic field.

26:07 Now from this side we'll be talking about how a magnet move.

26:11 Carrying charges from one place to another.

26:14 We'll talk about it and we'll talk about the factors that affect magnets, magnetic field.

26:20 Now like I said, the moving charge in the magnetic field will express a force.

26:26 The magnitude of the force depends on the following.

26:30 Now what are the following?

26:32 One.

26:33 It depends on this first one.

26:38 We'll talk about it depends on the charge.

26:43 It depends on the charge first.

26:46 That's the first thing.

26:47 It depends on the charge.

26:48 That means what, increasing what in the force will bring an increase what in the charge.

26:53 And vice versa.

26:54 Now we also have that.

26:55 There's always what, this can also affect the magnitude of the charge.

26:59 We affect the force.

27:02 The force.

27:03 Now, force also is directly proportional to the potential difference.

27:11 It simply means that what increase in the force will bring an increase in the potential difference.

27:16 That means this can also affect the force.

27:20 It can also affect moving charge of the magnets.

27:25 We also have the flux also, which is called the strength of the field.

27:31 Strength of the field is what the B from this side.

27:34 This can also affect these are the things that will affect the charge.

27:40 By solving it, we have, that's what, that's F, is equal to QVB.

27:49 Now, if an angle between the moving charge, if you have an angle that moves,

27:54 in that charge, we will have it towards that sine theta, we have that sort of F,

28:01 is equal to sine theta.

28:04 Now, when we bring these factors together, when we bring the factors together,

28:09 we have that sort that F is equal to QVB sine theta.

28:18 Now, from this place, now we said, now, this applies the bigger the force.

28:28 The bigger the force, the bigger the charge.

28:31 Likewise, the higher the force, the potential difference, the higher the frequency of the force, the higher this.

28:38 The higher the force, the higher the strength of the magnets.

28:41 That is why we have it to be this.

28:43 If this one decreases, this one decreases and vice versa.

28:47 Okay, let's look out.

28:54 Okay, if the charge is moving perpendicular, now, let's look out.

29:05 When a charge is moving perpendicular, that means, if it is moving perpendicular,

29:10 that is, on the parallel line, we have it to be, that our sine theta is equal towards,

29:17 that is, theta is equal towards 90.

29:21 Now, by sorting, I will say that what does sine 90, which is equal towards 1.

29:27 Then I will bring it back to this place and say that what, that our force,

29:32 which is equal towards q, v, b, times 1, which gives us f is equal to q, v, b.

29:45 Now, we can make use of this when we are not giving the angle, or when it is at perpendicular,

29:54 we will use, make use of this.

29:56 Then an angle is given to us, we will make use of the other function, which is this,

30:03 which is this one.

30:07 Now, let's have this one as 1.

30:15 Let's have this as another one.

30:22 So, let's look out. There is a formula when it is given us what?

30:27 F marks, we have that F marks, we give us F marks, we give us q, v, b.

30:40 Now, let's look out questions on inks.

30:54 From this, now, let's look at the question given to us.

30:57 We are find the magnetic force.

31:01 Experienced by an electron projected into a magnetic field, magnetic flux density,

31:08 10 Tesla with velocity of 6.7 times teris per 9 meter per seconds.

31:15 And in the direction, we have 80 degree, b, 30 degree, c, parallel to the magnetic feed,

31:24 as mean that the charge of the electron is 1.6 times teris per minus 19 coulomb.

31:32 Now, let's also get this.

31:35 Let's get our parameters.

31:37 We have the flux giving to us, flux giving to the flux density,

31:45 flux density, which is b, we have 10 Tesla.

31:54 We are giving the velocity, velocity, which is v, is equal to 6.7 times teris per 9 meter per seconds.

32:11 We are giving the charge of electron, which is q, is given us 1.6 times teris per minus 19 coulomb.

32:33 What else are we giving? We are giving an angle at 80 degree.

32:43 Now, our force is not given to always unknown.

32:47 Now, let's recall from force, recall.

32:54 We have force is equal to q, v, b, sin theta.

33:05 Now, what is our?

33:12 We have force is given to us.

33:16 Our charge is 1.6 times teris per minus 19.

33:21 Our velocity is given us 6.7 times teris per 9 times our flux density is given us 10 times sin 80.

33:44 Now, we have that our force is given. Let's make use of our calculator.

33:53 We have 1.6 times 6.7 times 10.

34:06 Now, give us 1.7.2 times 10 times 10 times sin 80.

34:35 Then, we have this to be f is equal to 10 times 7.2 times teris per minus 10 times sin 80.

35:02 From here, we have the force is equal to this point 2.

35:09 Now, we have to get sin 80 times this sin 80.

35:19 Because our calculator does not have sin 80, let's stop here.

35:24 So, you can use your calculator to get sin 80 that you multiply everything to get the answer in new thing.

35:34 Now, let's look at the second question which is b, b parts.

35:39 The same thing is applicable. Let's start from this place.

35:43 Let's start from this place.

35:45 Now, we are giving that words. The angle is what's angle 30 degree.

35:52 Now, let's use this from the force given to rows already.

35:58 From the force given to rows, which is what f is equal to 107.2 times teris per minus 10 times sin 30.

36:13 And sin 30 is what's sin 30 is equal to 0.5 or 1 over 2.

36:24 Then, graph f is equal to 10 more than 7.2 times teris per minus 10 times 0.5.

36:39 Now, let's make use of the calculator.

36:46 We have 107.2 times 0.5.

36:59 We give us 53.6. Give us f is equal to 53.6 times 10 to the power minus 10.

37:11 So, I can have it as shift this one once. Shift it once, I'll have that words.

37:24 f is equal to 5.36 times teris per minus 9 new thing.

37:34 That's the second answer for the b.

37:38 Now, the c is parallel to the magnetic field.

37:42 Now, when it is parallel to the magnetic field, when it is parallel to the magnetic field.

37:52 Now, c parallel, parallel.

37:59 So, let's get for the parallel, which is equal to what?

38:04 c is equal to 0.

38:07 Now, from here, we can say that word.

38:10 4 is equal to qvb sin 0.

38:16 Now, we already know this to be 107.2 times teris per minus 10.

38:25 Now, from this list, we will not have it to be.

38:33 This will force is equal to 1.7.2 times teris per minus 10 times sin 0.

38:46 sin 0 is equal to 1.

38:52 Sorry, that is 90.

38:55 That is 90, not 0.

38:59 So, 90.

39:01 So, 90.

39:03 So, 90.

39:05 And so, 90 is equal to 0.

39:08 Let's continue.

39:14 Now, from here, 90 we have f is equal to 107.2 times teris per minus 10 times 1.

39:24 We have f is equal to 107.2 times 10 is equal to minus 10 new sin.

39:34 So, this is the answer for the third one, which is the c.

39:41 That is, at the parallel, that means parallel to the magnetic field.

39:49 That is the answer.

39:53 That is the answer.

39:55 All right, you can go through these other ones.

40:01 You can go through these ones, look at these.

40:04 We are giving the charge.

40:06 We are giving the velocity.

40:08 We are giving the flux density.

40:11 We are giving the force.

40:14 We are actually looking for the force and the angle is giving to Ross.

40:16 We can use the same formula given to Ross.

40:19 Let me give you the hint for it.

40:21 Just use that f is equal to q, v, b, sin theta.

40:28 There is a formula you have to use to solve also, then you can make just this about it.

40:35 Thank you for watching.

40:37 I am Eminem Di John.

40:39 See you next time.