Magnetism and Matter (8 Nov)- Live session - NEET 2020Contact Number: 9667591930 / 8527521718

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Domain formation is the necessary feature of :

(1) ferromagnetism (2) diamagnetism

(3) paramagnetism (4) all of these

The best material for the core of a transformer is

(1) mild steel (2) stainless steel

(3) soft iron (4) hard steel

The north pole of a magnet is brought near a metallic ring.

Then the direction of the induced current in the ring will be:

(1) Towards north (2) Towards south

(3) Anticlockwise (4) Clockwise

Angle of dip is 90° at:

(1) Equator (2) Middle point

(3) Poles (4) None of these

What happens, when a magnetic substance is heated ?

1. | It loses its magnetism | 2. | It becomes a strong magnet |

3. | Does not effect the magnetism | 4. | Either (2) and (3) |

A magnet 10 cm long and having a pole strength 2 amp m is deflected through 30° from the magnetic meridian.

The horizontal component of earth’s induction is $0.32\times {10}^{-4}$ tesla then the value of deflecting couple is :

(1) $32\times {10}^{-7}$ Nm (2) $16\times {10}^{-7}$ Nm

(3) $64\times {10}^{-7}$ Nm (4) $48\times {10}^{-7}$ Nm

Which one of the following statement is not correct about the magnetic field ?

(1) Inside the magnet the lines go from north pole to south pole of the magnet

(2) Tangents to the magnetic lines give the direction of the magnetic field

(3) The magnetic lines form a closed loop

(4) Magnetic lines of force do not cut each other

Which one of the following is used to express the intensity of the magnetic field in a vacuum?

1. oersted

2. tesla

3. gauss

4. None of these

A frog can be levitated in a magnetic field produced by a current in a vertical solenoid placed below the frog.

This is possible because the body of the frog behaves as :

(1) paramagnetic (2) diamagnetic

(3) ferromagnetic (4) antiferromagnetic

Liquid oxygen remains suspended between two pole forces of a magnet because it is :

(1) diamagnetic (2) paramagnetic

(3) ferromagnetic (4) antiferromagnetic

The magnetic susceptibility of an ideal diamagnetic substance is

(1) –1 (2) 0 (3) +1 (4) $\infty $

A magnet makes 40 oscillation per minute at a place having magnetic intensity of 0.1 × ${10}^{-5}$ tesla.

At another place it takes 2.5 sec to complete one oscillation. The value of earth's horizontal field at that

place is

(1) 0.76 × ${10}^{-6}$ tesla (2) 0.18 × ${10}^{-6}$ tesla

(3) 0.09 × ${10}^{-6}$ tesla (4) 0.36 × ${10}^{-6}$ tesla

Curie temperature is the temperature above which

(1) a ferromagnetic material becomes paramagnetic

(2) a paramagnetic material becomes diamagnetic

(3) a ferromagnetic material becomes diamagnetic

(4) a paramagnetic material becomes ferromagnetic

Of the following Fig., the lines of magnetic induction due to a magnet SN, are given by

(i)

(ii)

(iii)

(iv)

(1) (i) (2) (ii) (3) (iii) (4) (iv)

The materials suitable for making electromagnets should have

(1) high retentivity and low coercivity

(2) low retentivity and low coercivity

(3) high retentivity and high coercivity

(4) low retentivity and high coercivity

Magnetic lines of force due to a bar magnet do not intersect because

(1) a point always has a single net magnetic field

(2) the lines have similar charges and so repel each other

(3) the lines always diverge from a single force

(4) the lines need magnetic lenses to be made to interest

At a temperature of 30°C, the susceptibility of a ferromagnetic material is found to be \(x.\) Its susceptibility at 333°C is:

1. \(x\)

2. \(0.5x\)

3. \(2x\)

4. \(11.1x\)

Two points A and B are situated at a distance x and 2x respectively from the nearer pole of a

magnet 2 cm long. The ratio of magnetic field at A and B is

(1) 4 : 1 exactly (2) 4 : 1 approximately

(3) 8 : 1 approximately (4) 1 : 1 approximately

Imagine rolling a sheet of paper into a cylinder and placing a bar magnet near its end as shown in the figure.

What can you say about the sign of $\stackrel{}{}$\(\vec{B}.d\vec{A}\)

1. positive

2. negative

3. no sign

4. can be positive or negative

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