Permanent Magnets Physics - Permanent Magnets

A circular loop carrying a current is replaced by ann equivalent magnetic dipole. A point on the axis of the loop is in:

1. End-on position.
2. Broadside-on position.
3. Both.
4. None.

A dip circle is taken to geomagnetic equator. The needle is allowed to move in a vertical plane perpendicular to the magnetic meridian. The needle will stay:

1. In horizontal direction only.
2. In vertical direction only.
3. In any direction except vertical and horizontal.
4. In the direction it is released.

A circular loop carrying a current is replaced by an equivalent magnetic dipole. A point on the loop is in:

1. End-on position.
2. Broadside-on position.
3. Both.
4. None.

A tangent galvanometer is connected directly to an ideal battery. If the number of turns in the coil is doubled the deflection will:

1. Increase.
2. Decrease.
3. Remain unchanged.
4. Either increase or decrease.

If the current is doubled, the deflection is also doubled in:

1. A tangent galvanometer.
2. A moving-coil galvanometer.
3. Both.
4. None.

Can the earth's magnetic field be vertical at a place? What will happen to a lreely suspended magnet at such a place? What is the value of dip here?

Can we have a single north pole? A single south pole?

Do two distinct poles actually exist at two nearby points in a magnetic dipole?

To measure the magnetic moment of a bar magnet, one may use:

1. A tangent galvanometer.
2. A deflection galvanometer if the earth's horizontal field is known.
3. An oscillation magnetometer if the earth's horizontal field is known.
4. Both deflection and oscillation magnetometer if the earth's horizontal field is not nown.

Sketch the magnetic field lines for a current-carrying circular loop near its centre. Replace the loop by an equivalent magnetic dipole and sketch the magnetic field lines near the centre of the dipole. Identify the difference.

Compare the direction of the magnetic field inside a solenoid with that of the field there if the solenoid is replaced by its equivalent combination of north pole and south pole.

An iron needle is attracted to the ends of a bar magnet but not to the middle region of the magnet. Is the material making up the ends of a bar magnet different from that of the middle region?

Two bar magnets are placed close to each other with their opposite poles facing each other. In absence of other force the magnets are pulled towards each other and their kinetic energy increases. Does it contradict our earher knowledge that magnetic forces cannot do any work and hence cannot increase kinetic energy of a system?