Moving Charge and Magnetism Chapter-Wise Test 2

Correct answer Carries: 4.

Wrong Answer Carries: -1.

A wire of length \( 2 \, \text{m} \) carrying \( 4 \, \text{A} \) is at \( 60^\circ \) to a magnetic field of \( 0.25 \, \text{T} \). What is the force on the wire?

\( F = I l B \sin \theta \).

\( F = 4 \times 2 \times 0.25 \times \sin 60^\circ = 2 \times 0.866 = 1.732 \approx 1.73 \, \text{N} \).

1 N
2.5 N
1.5 N
1.73 N
4

Why does a charged particle describe a circular path when moving perpendicular to a uniform magnetic field?

The magnetic force \( \mathbf{F} = q (\mathbf{v} \times \mathbf{B}) \) acts perpendicular to the velocity, providing the centripetal force needed for circular motion when the velocity is perpendicular to the field.

Due to gravitational force
Due to the magnetic force acting as centripetal force
Due to electric field influence
Due to frictional force
2

A long straight wire carries a current of \( 18 \, \text{A} \). What is the magnetic field at a distance of \( 0.15 \, \text{m} \) from it? (\( \mu_0 = 4 \pi \times 10^{-7} \, \text{T m/A} \))

Magnetic field \( B = \frac{\mu_0 I}{2 \pi r} \).

\( B = \frac{4 \pi \times 10^{-7} \times 18}{2 \pi \times 0.15} = \frac{72 \times 10^{-7}}{0.3} = 2.4 \times 10^{-5} \, \text{T} \).

2.4 × 10⁻⁵ T
4.8 × 10⁻⁵ T
1.2 × 10⁻⁵ T
3.6 × 10⁻⁵ T
1

A solenoid with 1500 turns per meter carries a current of \( 4 \, \text{A} \). What is the magnetic field inside the solenoid? (\( \mu_0 = 4 \pi \times 10^{-7} \, \text{T m/A} \))

Magnetic field \( B = \mu_0 n I \).

\( B = 4 \pi \times 10^{-7} \times 1500 \times 4 = 24 \pi \times 10^{-4} \approx 7.54 \times 10^{-3} \, \text{T} \).

7.54 × 10⁻³ T
3.77 × 10⁻³ T
1.88 × 10⁻³ T
5.02 × 10⁻³ T
1

What is the SI unit of magnetic field strength?

The SI unit of magnetic field strength is the tesla (T), defined as the field producing a force of 1 N on a 1 C charge moving at 1 m/s perpendicular to the field.

Ampere
Gauss
Weber
Tesla
4

Two parallel wires \( 0.02 \, \text{m} \) apart carry \( 5 \, \text{A} \) each in opposite directions. What is the force per unit length? (\( \mu_0 = 4 \pi \times 10^{-7} \, \text{T m/A} \))

\( f = \frac{\mu_0 I_1 I_2}{2 \pi d} \).

\( f = \frac{4 \pi \times 10^{-7} \times 5 \times 5}{2 \pi \times 0.02} = \frac{100 \times 10^{-7}}{0.04} = 2.5 \times 10^{-5} \, \text{N/m} \).

1.25 × 10⁻⁵ N/m
5 × 10⁻⁵ N/m
2.5 × 10⁻⁵ N/m
3.75 × 10⁻⁵ N/m
3

A wire of length \( 2.2 \, \text{m} \) carrying \( 3.5 \, \text{A} \) is at \( 60^\circ \) to a magnetic field of \( 0.2 \, \text{T} \). What is the force on the wire?

Force \( F = I l B \sin \theta \).

\( F = 3.5 \times 2.2 \times 0.2 \times \sin 60^\circ = 7.7 \times 0.2 \times 0.866 = 1.3336 \approx 1.33 \, \text{N} \).

0.77 N
1.33 N
2.66 N
1.54 N
2

A wire of length \( 0.6 \, \text{m} \) carrying \( 9 \, \text{A} \) is at \( 60^\circ \) to a magnetic field of \( 0.4 \, \text{T} \). What is the force on the wire?

\( F = I l B \sin \theta \).

\( F = 9 \times 0.6 \times 0.4 \times \sin 60^\circ = 2.16 \times 0.866 = 1.8706 \approx 1.87 \, \text{N} \).

1.08 N
2.16 N
1.5 N
1.87 N
4

A rectangular loop of area \( 0.07 \, \text{m}^2 \) with 12 turns carries \( 3.5 \, \text{A} \) in a field of \( 0.5 \, \text{T} \) at \( 60^\circ \) to the plane. What is the torque?

\( \tau = N I A B \sin \theta \), where \( \theta = 60^\circ \) to plane means \( \sin 30^\circ \) with normal.

\( \tau = 12 \times 3.5 \times 0.07 \times 0.5 \times \sin 60^\circ = 1.47 \times 0.866 = 1.273 \approx 1.27 \, \text{N m} \).

0.74 N m
2.54 N m
1.27 N m
1.91 N m
3

A rectangular loop of area \( 0.04 \, \text{m}^2 \) with 25 turns carries \( 3 \, \text{A} \) in a field of \( 1.2 \, \text{T} \) perpendicular to the plane. What is the torque?

\( \tau = N I A B \sin \theta \), \( \theta = 90^\circ \) to plane means \( \sin 0^\circ = 1 \) with normal.

\( \tau = 25 \times 3 \times 0.04 \times 1.2 \times 1 = 3.6 \, \text{N m} \).

1.8 N m
7.2 N m
2.4 N m
3.6 N m
4

Performance Summary

Score:

Category Details
Total Attempts:
Total Skipped:
Total Wrong Answers:
Total Correct Answers:
Time Taken:
Average Time Taken per Question:
Accuracy:
0