# Electromagnetic Induction (EMI) : CBSE Class 10 Science

Electromagnetic Induction Students, this is one of the deep topics of physics which has very deep applications at different places, but before understanding this, we will see What is Galvanometer? Students, you will see there is a one simple instrument one device. What this does is let me tell you You can connect this device to any electric circuit. suppose, you connect it. This is the symbol for it, this makes a circle from it, and named as G. Now, you have connected it with one electric circuit. maybe there is some current flow from the electric circuit If the current flow from that electric circuit then what happens as you can see there is a one needle This needle will deflect if current flow like this then the needle deflects like this. Normally it is straight, deflect like this. If you connect it with any circuit and current flow like this then you will understand that needle deflects like this and after the connection, if it doesn’t flow any current then what happens? then you will understand that needle keep straight like this. So that is the main thing about this instrument. so see that, the work of this instrument It will tell you that the current is flowing or not If you have connected it and if the current does not flow from it then needle doesn’t deflect and if the current is flowing then it will deflect. so we can write as, Galvanometer tells us if the current is flowing or not. Besides that, it also tells us if the current flow is flowing then in which direction it flows? isn’t it. Look here, from these two it describes the direction of current so we can write, Galvanometer also tells us a direction of the current. Now, let’s see What is Electromagnetic Induction? So, students, we take one coil-like this there is one conducting wire, which we wind like this you can also think of it as a solenoid. Now at both ends of it, between them, we connect the galvanometer like this. You can understand that right now neddle of the galvanometer is straight, because there is no current is flowing from it. Now, we take one magnet. it has two poles, a north pole, and a south pole. and right now the magnet is on rest. also, look at the needle. There is no current is flowing, but, you can see one amazing thing, when I move this magnet. By moving this magnet, you can see that the needle will start deflecting. I will show you, as we move the magnet here, the needle deflects. What’s the meaning of it? It means that when the magnet move here, then the current is flowing from this circuit, that’s why the needle deflects. The deflection of the needle describes that current is flowing from it. once again see, right now the magnet is on rest, so the needle is not deflecting so there is no current. But when you move it here, the needle start deflects means the current is flowing from it. Why it happens, students? why? I will tell you, just wait for it, few more things to be observed here. Now students, let’s move this magnet in this direction, now, what’s happening student? now the needle is deflecting in other direction, means the current is still flowing but in a different direction. have you understood it? Students, one more thing we can do, now invert this magnet. so its south pole comes here and north pole comes here. now you can see all things are inverted. If you move magnet here, then the needle deflect there, now move magnet there then the needle deflects here. Means the point is, whenever the magnet moves, the current starts flowing in the loop. And the direction can also be changed depending on what are you doing here. So, first of all, we will write these observations, after that, we will see the reason behind it. So let me write these students, when the magnet moves, current flows in the coil. The direction of the current can be reversed By changing the direction of motion of the magnet or by changing its polarity. Right students, this is what we see. Now we will see that, why does it happen? So you can see, the magnets will have its field lines. all the mystery is hidden in these field lines. Now, these field lines are on the coil also, cross the coil. So we mark out the region of the coil with little circle mark, because we have to focus on it. Now see, when I move this magnet here, you have to observe what happens to the region of the coil, and how the field lines changed. So we move the coil here, it’s moving now see here, Is the magnetic field lines are changing in this region? Is the magnetic field changing in this region? obviously, it’s changing. Let’s try once again. Watch it, when it moves here, in this region, the magnetic field changes filed lines move ahead. Means, in that region the value of the magnetic field changes in reference to the time. When you move it, then the magnetic field lines changed in that region. right, students. What happened is, There is a law in physics, When a magnetic field changes with time through a coil, then current flow in that loop. are you understand it? If in any loop or in any coil, because of any reason the magnetic field changed, then current start flows in that coil. That’s why the current flow in this coil. So when you move it, the magnetic field changes in this coil, that’s why the current flows. When you move it far from it, see, is that the magnetic field is still changing? Yes, obliviously it changing. That’s why the current flow at that time. I hope you understand this. So, students, we can write it as, when magnetic field changes with time through a coil, current flows in that coil. This phenomenon is called Electromagnetic Induction. In short EMI. So, students, this phenomenon is called Electromagnetic Induction. In short EMI. EMI E for Electro M for Magnetic I for Induction. I hope you get this. Now, I tell you one more interesting thing about it, see, this time I fix the magnets. it’s on a rest. I will not move the magnet. This is a coil, supposed that I move this coil here, then you tell me what happens? What do you think? What will happen, if I move this coil here? I did not move the magnet even if in this coil, magnetic field changes? See, we move it from here then still magnetic field changes. So the needle is deflected and current flow in this case. Do you understand? So if you rest the magnet and move the coil, it still flows the current because still the field still changes you can also try by doing it reverse, if you move it here, the field still changes. so the current is also flowing in this case. So, students, the point is, If you move any from these two, the magnetic field changed from this coil in both cases. So, in both cases the current flows from it. So, students, we can write it as, Current flows through the coil, either move magnet or the coil itself. right, I am sure students, you understand the electromagnetic induction which I explained to you. You will understand it. If there is any doubt in your mind, then rewind the video and look back. Now I explain the one more example for electromagnetic induction, Once again we have that coil with a galvanometer, and here, we take one more coil but in this case, we are connecting one battery, one switch. Now the switch is open, current is not flowing from it. here, a very interesting observation is to be done, now watch, focus on this needle What I m doing is, turn ON the switch. So what happens I turn ON the switch. You observed what happens? The needle is deflected, but it backs to come to zero. Once again I do it, turn it ON, can you observe that the needle is deflected and come back to zero? What was the meaning of it? It deflects means current flows, and came back to zero, means current is zero. It means that when you turn ON the switch, the moment when you turn ON it, current flows from it and then it becomes back to zero. That’s why the needle back to zero. What happens here? First of all, why the current flow and after that why it become zero? Did you understand what I want to say? See, I describe you, Suppose the switch is OFF right now, again I make the same situation. There is our switch, if the switch is ON, current flows here because of that current, there are magnetic field lines available which also overpass the coil right, now the thing is to understand that when the switch is OFF, there is no magnetic field available. As you turn ON the switch, the magnetic field arrived. So you can see that the magnetic field changed from coil It is zero in starting, and then it gets higher. so from it, the magnetic field changed. so as you turn ON the switch, the magnetic field changed. according to the concept of electromagnetic induction, current should flow because the magnetic field changed, that’s why the needle is deflects Now why it does not deflect and came back to zero? Because you keep the switch ON, the field remains the same current keeps flowing and field remains the same. So the magnetic field on the region of the coil, the magnetic field is the same as it goes higher, it does not change. also, keep in mind that you are not moving anything, so the magnetic field which you can see in the coil, it remains the same. It means it does not change. so if magnetic fields do not change, then current will not flow from it. that’s why needle came back to zero. The electromagnetic induction says that, if the magnetic field changed from the loop, then current will flow. If the magnetic field is only there in the loop but it does not change, then current will not flow. it should be changed, rising or falling then current will flow. So when you turn ON the switch, there is no magnetic field and then suddenly it arrives means it changes that’s why current flow. But if you keep it ON, it does not change and remains the same. that’s why current is not flowing. I hope you understand this. Now it might be reversed, supposed that, if I turn OFF the switch, means opened it, say as turn OFF from ON then what happens? In this case, the needle will deflect and then back to zero. In this case, the deflection is in the opposite direction. You will understand why it happens, There is seen where the magnetic field is available, as you turn OFF the switch, magnetic filed goes away. so there is a change in a magnetic field. Earlier it’s there and now it is zero, so it is changed. so the current will flow because of electromagnetic induction, and the needle will deflect. But after that, the needle will again back to zero, because after that you keep it turn OFF, so there is no changed happens and the needle remains on zero and there is no current is flowing. So, I hope you understand this student, If you don’t understand then try a little bit harder, sometimes student gets confused in this, but actually, it is the same as this. Now I write it move it a little bit so that we have space, when switch is turned ON, current flows for a moment. right, when switch is turned OFF then also current flows for a moment but in opposite direction. right.

## 100 thoughts on “Electromagnetic Induction (EMI) : CBSE Class 10 Science”

1. Keep Learning says:

Sir your teaching style is fabulous but Sir you are not intelligent and not genius and you can't be a genius and intelligent because you are the father of genius not father but grandfather no you are the god of genius I mean aap genius se bhe genius ho I hope you understand what actually I want to say right

2. Ananya Shree says:

REALLY SIR U R FAB……..U CLEARED ALL MY DOUBTS

3. Sunita Gupta says:

This video is very helpful thanks for making this video

4. Bhola Singh says:

Please cover all the topics present inthe chapter . But ya your teaching had some magic ..
Thankyou sir..

5. Rockey Rockey says:

Make all the chapters video plz

6. Fatema Daudi says:

Sir can we produce electricity by electro magnetic force & Feild

7. Gaurav Raj says:

8. Jayant Sharma says:

Sir agar magnet constant h to current will flow or not or circuit is also in rest

9. arif mirza says:

Nicevedio sir i have no word this vedeio

10. Praseeda A says:

I was absent in school when this portion was taught but after watching this video I understand perfectly . Thank you Sir

11. ہم علی ع والے says:

Sir mujeh ppi drug ka.mode of action ki koi asaan vedio send kar dijye sir

12. Maqsood Alam says:

what is potancial difference ,omh's low and how electricity is produce explain this topics please

13. Arsalan Masood says:

Very nice ,very nice and mind blowing explanation, sir.
Thank you very much.

14. Arsalan Masood says:

Why magnetic field always arise from North pole and merge at south pole ?

15. Sushila devi Sonawat says:

I want a video on working of dc and ac motor

16. Isha Ghosh says:

Sir u taught very well n now my concept is very clear n well versed with it but how could I link to ur other videos , I'm not getting it

17. Shrink Music says:

Sir agar isko baar baar off on karenge tb to electricity generate ho sakta h na

18. Sukhveer Gill says:

What is uses of induction

19. Subodh Singh says:

But sir the results of emi is?????????… You 👉not give in this theory so plz give the results of emi

20. knowledge Kingdom says:

Outstanding. ..👌mind blowing sir. ..

21. tech guru says:

Thank you sir you are best teacher i ever seen

Sir bas aaise hee sara video upload kigye

23. Sheikh Mujiburrahman says:

Awesome video sir
But full chapter or numericals solving video bhi rakheana plz plz plz sir

24. Govind Raj says:

Nice

25. Bidhan hajong says:

best hai apka explanation

26. Praveen arora says:

Sir electric motor pe banao

27. ANGRY MANAV says:

Nice

28. Aalam Nezami says:

Thankuu sooo much sir, only bcz of u I m able to understand this topic clearlyy

29. Aman Rathod says:

Sir your confidence is great .

30. vicky mandal says:

Sir app to bhayank samjhate ho thanku Sir and

31. ghulam mustafa says:

Thanks soooo much sir ap ny to meri mushkil hi asan kr di

32. Rashid Intizar says:

i new student…. but good method …..please more example ……

33. lιFє ιѕ Fυи says:

PHYSICS WALA IS BEST😂😂

34. Aksa Panhyar says:

Amazing

35. pan machine says:

ybas paise ke liye padhata hai

36. Loveleen Kaur says:

Excellent job

37. sagar motankar says:

Really nice video sir, your teaching techniques and method is excellent sir

38. Kajal Sharma says:

Sir AAP jish tarike se samshate ho ush tarike se padh kar pura samash aa jaata hai thanks sir teaching me

39. YASHU GUPTA says:

40. vinod choudhary says:

Plse sir make video on electric motor and generator

41. Kirat Sidhu says:

Love the animation bcoz its better for understanding

42. Shikha verma Shikha verma says:

Sir aap to genius ho ( I have understood very well) thanks a lot

Sir please s.st ke bhi animated video banaye. Bahut views mile ga.
Friends dhoko like

44. Diwakar Jatav says:

Sir right hand thumb pr vdo upload kr do sir plz plz plz………

45. kartikey bartwal says:

Loved the video sir !!!

46. Rani verma says:

Voice modulations are perfect sir with teaching style

47. Rihan Khan says:

sir thank you so much sir…i think esse achcha lecture khi or dekhne ko nhi milega

48. phone and PC new functions tv says:

Very well lecture (Pakistan)

49. Harshit Kumar says:

Sir plzzz make video on electric motor

50. satyam singh says:

Bro chila kyu raha hai tu

51. Shahama Khalid says:

U are a best teacher. You make any of the boring topic very interesting😀

52. Sawan kumar says:

You r amazing

53. Sawan kumar says:

Sooperb sir

54. Mahi redimed mustak says:

Sir your teaching style is very nice and this video is also very nice

55. AK Mahakal says:

Nic

56. Prince Rai says:

I respect you so much sir
Because your teaching style is so good
I love it so much sir ❤️❤️❤️

57. Prince Rai says:

58. #karan kumar says:

Well done sir

59. #karan kumar says:

Sir please make full chapter videos

60. Disha Urmale says:

Sir….your explanation was wonderful……….is wonderful ….and will being very nice always….😃

61. Iqra Shaikh says:

Amazing 👌👍😍🙌🎉
I hope u understand this 😅🤗

62. Supriya Deb says:

I understood

63. apex says:

Students = 100..times.
Nice way of teaching

64. Gourav Dang says:

Sir can we glow a electronic bulb of 20 -30 watt by this ?

Sir u r great ….ur way of teaching is fabulous ,fantastic..there's no word to explain how much happy i am bcoz my all doubts have been cleared related to EMI …..😊😊😊

Jabardast

Very good explanation thank u sir

68. hitesh bora says:

Nice sir

69. Nishtha Majumder says:

Sir thanku alot.. Ye apka pehla video mene dekha… Thnku sir bhot acche se samjhaya he apne

Sir plzz make a vidio of a complete chapter.

71. jinay Shah says:

Sir you r papa of neuton🤣

72. Sujal farke says:

Superb explanation 👍👍👍

73. Sanjanaraj Varshney says:

What a explanation nice

74. Мя-Їйтєяйдтїойдl says:

can we glow a 100 W bulb with 40 W of current

75. Akash Kumar says:

Thank you so much sir

Sir electronic moter and generator pa v vedio dejea na

77. Mohammed Azmathulla says:

my name is taj and iam studying in 10 standard it helps me to easy to learn lesson actually I have seen only 2 /3 lessons thank you so much

78. Nidhi sinha says:

Great explanation sir thanks

79. Mahi Sharma says:

Best

80. Arun Vishwakarma says:

You are great sir good explanation

81. pravin singh says:

Sir jab current off karenge to galvanometer opposite direction me kaise deflect karega

82. Umesh Verma says:

Thanks sir❄️👍👍👍👍👍👍

83. Umesh Verma says:

Sir electromagnetic waves per video kab banayege👆👆👆👆👆👆👆👆👆👆👆☝️☝️☝️??????!

84. shahbazuddin shaikh says:

Thank u sir

Don't you think he looks like Arwind Kejriwal ✨🌺🌺✨🌺🌺✨
🌺🌺🌺🌺🌺🌺🌺
🌺🌺🌺🌺🌺🌺🌺
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86. Mukesh Kuriya says:

How demagnetizer work

87. SOUL CITY gamer says:

Thank you sir

88. Reena Gupta says:

so, sir tell me when we put our phone on wireless charger why current flows in it as you have said current can't flow if solenoid doesn't moves

89. Harsh Choudhary says:

sweetheart as quit

90. As Jhothi says:

Waaaa super

91. Abid Sarfraz says:

sir aap science ka aasa saara vedio banado

subscribe kar Diya hun!!

92. Manjit Sidhu says:

Brilliantly explained sir …thank you

Thank u

94. vaibhav tiwari says:

Sir what are mean by induced current please tell ,me about that

95. Raj Verma says:

Nice

Wahh sir accha samjhate h aap

97. Nagarajan Iyer says:

98. Atul Maurya says:

Electric motor

99. PIYUSH KUMAR says:

Sir l want to next video

100. Bashar Akhter says:

You born to teach hard