Advertisements
Advertisements
Question
Describe briefly one way of producing an induced current in a coil. State one factor that determines the magnitude of induced e.m.f.
Advertisements
Solution
To produce an induced current in a coil, a magnet is moved along the axis of coil. The magnitude of induced e.mi. depends on the strength of magnet.
RELATED QUESTIONS
Tick the most appropriate answer.
Which of the following methods is used to magnetize a magnetic without touching it by a magnet?
principle of an electric motor ?
Name the material of core in (a) an electric bell, (b) electromagnet, (c) a d.c. motor, (d) an a.c. generator and (e) a transformer.
Name the type of transformer shown in Fig. What changes will you observe regarding the brightness of the lamp, if
- the number of turns in the secondary is doubled? Explain.
- the part X of the transformer is removed?
- the core of the transformer is made out of copper?
- the A.C. supply is replaced by D.C.?

A straight wire is held vertical and current is passed in it in the upward direction. A compass needle is kept near the wire in north of it. How is the needle deflected? What is the change in the deflection of the needle if the current in wire is reversed?
Why is soft iron generally used as the core of the electromagnet?
State two advantages of an electromagnet over a bar magnet.
What will be the effect on the working of an electric bell if instead of a direct current an alternating current is used?
What is dynomo (a.c. generator)? State the principle on which it works.
The primary windings of a step-up transformer are usually made of thicker wire than the secondary. Explain.
