Electromagnets

Q. Which of the following is not true about electromagnets?

1. The magnetic property is caused due to the flowing current.
2. Poles can be interchanged.
3. Electromagnets are temporary magnets.
4. The magnetic strength cannot be changed.

Q.

Choose the correct statements from the below mentioned statements:-

1. Electromagnets are made of soft iron while permanent magnets are made of steel.

2. Polarity of an electromagnet can be reversed but polarity of permanent magnet cannot be reversed.

3. Magnetic field of electromagnet is weak while magnetic field of permanent magnet is very strong

4. Electromagnet cannot be easily demagnetised while permanent magnet can be easily demagnetised.

Q.

Branch of physics which deals with magnetic effects of electric current is called:-

1. Magnetism

2. Electromagnetism

3. Electrostatics

4. Electromagnetic induction

Q.

Suppose we have a solenoid with two ends A and B. If current at face A is clockwise while at B is anticlockwise. So, A and B act as:-

1. A as north pole and B as south pole

2. B as north pole and A as south pole

3. Both A and B as north pole

4. Both A and B as south pole

Q.

Which among the following works on the basis of magnetic effect of electric current?

1. Electromagnet

2. Electric heater

3. Electric fuse

4. Electric press

Q.

Working of an electromagnet is based on ___.

1. Heating effect of electric current

2. Electro-chemical effect of electric current

3. Magnetic effect of electric current

4. Chemical effect of electric current

Q.

A crane uses a mysterious object ‘X’ to separate magnetic materials from junk. The object ‘X’ is most probably

1. Electromagnet

2. Permanent magnet

3. Magnetic material

4. None of the above

Q.

Electromagnets are permanent magnets.

1. True

2. False

Q. ___are used in the heavy cranes to pick heavy metallic objects in different industries.

Q.

Study the statements given below:
(i) Electromagnets can be made more powerful than ordinary bar magnets.
(ii) Soft iron is easy to magnetize and demagnetize.
(iii) The poles of an electromagnet are not affected by the direction of the current.
Which of the above statements about the electromagnets are correct?

1. Only (i) and (ii)

2. Only (ii) and (iii)

3. (i), (ii) and (iii)

4. Only (i) and (iii)