Advertisements
Advertisements
Question
How will you make an iron bar electromagnet? Draw a diagram showing the polarities of the electromagnet?
Advertisements
Solution
Take the given iron bar AB. Wound several turns of insulated copper wire over the bar. Connect the ends of the wire to a battery through a switch. Press the switch to pass current. After some time, the bar AB becomes a magnet.
The end A of the bar at which the current enters the coil in clock¬wise direction becomes the south pole (S) and the end B of the bar at which the current leaves the coil in anti-clockwise direc¬tion becomes the north pole (N).
APPEARS IN
RELATED QUESTIONS
State three uses of an electromagnet?
State two differences between an electromagnet and a permanent magnet.
Name the material used for making the armature of an electric bell. Give a reason for your answer.
What is an electric motor?
Fill in the blanks by writing (i) Only soft iron, (ii) Only steel, (iii) Both soft-iron and steel for the material of core and/or magnet.
Electric bell ______.
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 strength of current in the solenoid is decreased?
State the position of armature coil relative to the direction of magnetic field, in a D. C. motor when the deflecting couple acting and the coil is minimum.
What is dynomo (a.c. generator)? State the principle on which it works.
State important properties (or characteristics) of magnetic lines of force around a straight conductor.
