Advertisements
Advertisements
प्रश्न
What is a permanent magnet? Give one use of it.
Advertisements
उत्तर
A permanent magnet is a magnet made from steel such that once magnetized, it does not lose its magnetism easily. Use: It is used in the galvanometer.
संबंधित प्रश्न
State two ways of magnetising an iron piece?
Suppose you are given a long bar magnet and you are asked to break it into four small magnets. Draw diagrams showing the polarities of each broken part.
You are given an iron nail, a torch cell, and a long piece of insulated copper wire. With the help of a labelled neat diagram, describe in steps how you will make the nail, an electromagnet.
Name and state the rule by which polarity at the ends of a current carrying solenoid is determined.
principle of an electric motor ?
Name the type of transformer shown in fig . What changes will you observe regarding the brightness of the lamp, if
(a) The no. of turns in the secondary is doubled?
(b) The part X of the transformer is removed?
( c) The core of the transformer is made out of copper?
(d ) The A.C. supply is replaced by D.C.?
State two factors on which the magnitude of an induced e.m.f. in the secondary coils of a transformer depends.
How does a magnetic field set up by a solenoid change when a soft iron core is inserted inside solenoid?
State the principle of a D. C. motor.
State important properties (or characteristics) of magnetic lines of force around a straight conductor.
