Earth's Magnetic Field

Q.

State two evidences of the existence of earth's magnetic field.

Q.

Where is the strength of earths magnetic field maximum and minimum?

Q.

Earth's magnetic field lines are parallel to earth surface near magnetic poles and normal to earth surface near magnetic equator:-

1. True

2. False

Q. Compass placed near a current carrying wire undergoes deflection, because of the of the current flowing through it.

1. heating effect
2. magnetic effect
3. chemical effect

Q.

The two places where magnetic needle becomes normal to earth surface are called___.

Q.

The line joining the places where the magnetic needle becomes horizontal is called___.

Q.

A magnetic compass does not show any particular direction at the magnetic poles.

1. True
2. False

Q. At the magnetic __________, the earth’s magnetic field lines are parallel to the surface whereas at the magnetic ________, they are normal to the surface.

1. $\text{N}$ pole only, equator
2. equator; $\text{N}$ and $\text{S}$ poles
3. $\text{N}$ and $\text{S}$ poles; equator
4. equator; $\text{S}$ pole only

Q.

A freely suspended magnet aligns itself in the north-south direction in a room and air is sucked from that room through the vacuum pump. So, now there is no air in the room but still, the magnet aligns itself in the north-south direction.

1. True

2. False

Q. A freely suspended bar magnet always aligns itself in the North-South direction.

1. False
2. True

Q.

A compass has a small balanced pointer that always points North-South. This is because:

1. The stars exert a force on the needle

2. Gravity makes the needle point this way

3. The earth has a magnetic field and the pointer is magnetic

4. The compass needle points to cold places

Q. Any magnet suspended freely points to one direction because the Earth acts as a magnet.

1. True
2. False

Q. we are told that we should not keep our mobile phones in external magnetic .the earth has its magnetic fields why is it not effecting to our mobile phones

Q.

The magnetic field lines of the earth are

1. normal to the earth's surface near the magnetic poles

2. parallel to the earth's surface near the magnetic poles

3. at an angle to the earth's surface near the magnetic poles

4. normal to the earth's surface near the magnetic equator

Q. Compass placed near a current carrying wire undergoes deflection, because of the of the current flowing through it.

1. heating effect
2. magnetic effect
3. chemical effect