# Magnetic Effects of Current and Magnetism (NEET Physics): Questions 73 - 78 of 155

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## Question number: 73

» Magnetic Effects of Current and Magnetism » Electric Charge Moving in Magnetic Field

MCQ▾

### Question

An electron is revolving in a circular path of radius 2 x l0 -10 m with a speed of 3 x l0 6 m/s. The magnetic field at the center of circular path will be

### Choices

Choice (4) Response

a.

0

b.

1.2 T

c.

2.4 T

d.

3.6 T

## Passage

A telephone cable at a place has four long, straight horizontal wires carrying a current of 1.0 A in the same direction east to west. The earth’s magnetic field at the place is 0.39 Gauss, and the angle of dip is 35°. The magnetic declination is nearly zero, (cos 35° = 0.82, sin 35° = 0.57)

## Question number: 74 (1 of 3 Based on Passage) Show Passage

» Magnetic Effects of Current and Magnetism » Earth's Magnetic Field

MCQ▾

### Question

The magnetic field produced by four current carrying straight cable wires at a distance 4 cm is

### Choices

Choice (4) Response

a.

0.3 Gauss

b.

0.2 Gauss

c.

0.5 Gauss

d.

0.4 Gauss

## Question number: 75 (2 of 3 Based on Passage) Show Passage

» Magnetic Effects of Current and Magnetism » Earth's Magnetic Field

MCQ▾

### Question

The resultant magnetic fields below at points 4cm and above the cable are

### Choices

Choice (4) Response

a.

0.25, 0.56 Gauss

b.

0.23, 0.34 Gauss

c.

0.14, 0.32 Gauss

d.

0.52, 0.62 Gauss

## Question number: 76 (3 of 3 Based on Passage) Show Passage

» Magnetic Effects of Current and Magnetism » Earth's Magnetic Field

MCQ▾

### Question

The angle that resultant makes with horizontal in case below and above the cable respectively, are

### Choices

Choice (4) Response

a.

b.

30°, 45°

c.

d.

## Question number: 77

» Magnetic Effects of Current and Magnetism » Electric Charge Moving in Magnetic Field

MCQ▾

### Question

An α-particle is describing a circle of radius 0.45 m in a field of magnetic induction 1.2 weber/m 2. The potential difference required to accelerate the particle, (The mass of a-particle is 6.8 x 10 -27 kg and its charge is 3.2 x 10 -19 coulomb. ) will be

### Choices

Choice (4) Response

a.

2.3 x 10 -12 V

b.

6 x 10 6 V

c.

7 x 10 6 V

d.

3.2 x 10 -12 V

## Question number: 78

» Magnetic Effects of Current and Magnetism » Electric Charge Moving in Magnetic Field

MCQ▾

### Question

If an α-particle moving with velocity V enters perpendicular to a magnetic field then the magnetic force acting on it will be

### Choices

Choice (4) Response

a.

2evB

b.

4evB

c.

0

d.

evB

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