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प्रश्न
List some of the practical applications of an electromagnet.
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उत्तर
Electromagnets are used to lift heavy loads of scrap iron etc., to separate magnetic substances from non-magnetic ones and in devices like the electric bell, telegraphs, telephones, loud speakers, etc.
संबंधित प्रश्न
A line charge λ per unit length is lodged uniformly onto the rim of a wheel of mass M and radius R. The wheel has light non-conducting spokes and is free to rotate without friction about its axis (Figure). A uniform magnetic field extends over a circular region within the rim. It is given by,
B = − B0 k (r ≤ a; a < R)
= 0 (otherwise)
What is the angular velocity of the wheel after the field is suddenly switched off?
State whether the following statement are true or false:
A motor works on the principle electric generator?
Describe different ways to induce current in a coil of wire.
The diagram 10 shows two coils X and Y. The coil X is connected to a battery S and a key K. The coil Y is connected to a galvanometer G.
When the key K is closed. State the polarity
(i)At the end of the coil X,
(ii)At the end C of the coil Y,
(iii)At the end C of the coil Y if the coil Y is (a) Moved towards the coil X, (b) Moved away from the coil X.
Draw a labelled diagram to show how an electromagnet is made.
Which of the following scientist invented the rule of electromagnetic induction?
State Fleming’s right-hand rule.
An induced current of 2.5 mA flows through a single conductor of resistance 100 Ω. Find out the rate at which the magnetic flux is cut by the conductor.
A metal plate can be heated by ______.
The working of a dynamo is based on the principle of
