Electromagnetism and Electromagnet

Q.

How is an electromagnet made? Name two factors on which the strength of magnetic field of the electromagnet depends.

Q. Give scientific reason. The copper wire used in an electromagnet is insulted.

Q.

The factors that affect the strength of a magnetic field at a point due to a straight conductor carrying current are:

1. None of these.

2. Magnitude of the electric current.

3. Both A and B.

4. Perpendicular distance between the point and the conductor.

Q.

If a current carrying conductor is placed near a heap of iron filings, we can observe some disturbance in iron fillings because of________.

1. Electric field produced by current

2. Magnetic field produced by current

3. Gravitational field

4. None of these

Q. Iron filings are sprinkled on a cardboard perpendicular to which a current carrying copper wire flows as shown.

What happens to a compass at the point P, if the current through the circuit is increased? (Ignore the magnetic field of the Earth.)

1. The compass deflects more
2. The compass deflects less
3. The compass needle wont deflect
4. The direction of the compass needle reverses

Q. To produce a magnetic field of pi tesla at the centre of circular loop of diameter 1m, the current flowing through loop is ?

Q.

Write any four uses of electromagnets.

Q.

State four uses of magnets/electromagnets.

Q.

Look at the figure given below and answer the question based on that.

Iron filings are sprinkled on a cardboard perpendicular to which a current carrying copper wire runs. The other components of the circuit have their usual meanings

What happens to a compass at a particular point near the copper wire if the resistance of the circuit is increased?

1. The deflection of the compass is increased.

2. The deflection of the compass is decreased.

3. The direction of the compass needle is reversed.

4. Nothing happens

Q. STATEMENT-1
The sensitivity of a moving coil galvanometer is increased by placing a suitable magnetic material as a core inside the coil.
STATEMENT-2
Soft iron has a high magnetic permeability and cannot be easily magnetized or demagnetized.

1. STATEMENT-1 is True, STATEMENT-2 is True; STATEMENT-2 is NOT a correct explanation for STATEMENT-1
2. STATEMENT -1 is True, STATEMENT-2 is False
3. STATEMENT-1 is True, STATEMENT-2 is True; STATEMENT-2 is a correct explanation for STATEMENT-1
4. STATEMENT -1 is False, STATEMENT-2 is True

Q.

how to determine in which direction will the needle of the compass will rotate when it is brought near a magnet and also a circuit

Q.

For making a strong electromagnet, the material of the core should be:

1. Soft iron

2. Steel

3. Brass

4. Copper