NEET Magnetic Effects of Current and Magnetism — Set 8

Question 1

A wire of length $ 0.8 \, \text{m} $ carrying $ 3 \, \text{A} $ makes an angle of $ 30^\circ $ with a magnetic field of $ 0.6 \, \text{T} $. What is the force on the wire?

Accepted Answer

Force $ F = I l B \sin \theta $. $ F = 3 \times 0.8 \times 0.6 \times \sin 30^\circ = 2.4 \times 0.6 \times 0.5 = 0.72 \, \text{N} $.

Question 2

Two parallel wires $ 0.03 \, \text{m} $ apart carry currents of $ 10 \, \text{A} $ and $ 2 \, \text{A} $ in the same direction. What is the force per unit length between them? ($ \mu_0 = 4 \pi \times 10^{-7} \, \text{T m/A} $)

Accepted Answer

Force per unit length $ f = \frac{\mu_0 I_1 I_2}{2 \pi d} $. $ f = \frac{4 \pi \times 10^{-7} \times 10 \times 2}{2 \pi \times 0.03} = \frac{80 \times 10^{-7}}{0.06} = 1.333 \times 10^{-5} \approx 1.33 \times 10^{-5} \, \text{N/m} $.

Question 3

A long straight wire carries a current of $ 22 \, \text{A} $. What is the magnetic field at a distance of $ 0.2 \, \text{m} $ from it? ($ \mu_0 = 4 \pi \times 10^{-7} \, \text{T m/A} $)

Accepted Answer

Magnetic field $ B = \frac{\mu_0 I}{2 \pi r} $. $ B = \frac{4 \pi \times 10^{-7} \times 22}{2 \pi \times 0.2} = \frac{88 \times 10^{-7}}{0.4} = 2.2 \times 10^{-5} \, \text{T} $.

NEET Physics: Magnetic Effects of Current and Magnetism — Practice Set 8

Q1. A wire of length \( 0.8 \, \text{m} \) carrying \( 3 \, \text{A} \) makes an angle of \( 30^\circ \) with a magnetic field of \( 0.6 \, \text{T} \). What is the force on the wire?

Q2. Two parallel wires \( 0.03 \, \text{m} \) apart carry currents of \( 10 \, \text{A} \) and \( 2 \, \text{A} \) in the same direction. What is the force per unit length between them? (\( \mu_0 = 4 \pi \times 10^{-7} \, \text{T m/A} \))

Q3. A long straight wire carries a current of \( 22 \, \text{A} \). What is the magnetic field at a distance of \( 0.2 \, \text{m} \) from it? (\( \mu_0 = 4 \pi \times 10^{-7} \, \text{T m/A} \))

Q4. A straight wire of length \( 0.9 \, \text{m} \) carries a current of \( 7 \, \text{A} \) perpendicular to a uniform magnetic field of \( 0.2 \, \text{T} \). What is the force on the wire?

Q5. A circular coil of radius \( 0.04 \, \text{m} \) with 50 turns carries \( 1.8 \, \text{A} \). What is the magnetic field at the center? (\( \mu_0 = 4 \pi \times 10^{-7} \, \text{T m/A} \))

Q6. A wire of length \( 1.6 \, \text{m} \) carrying \( 5 \, \text{A} \) is at \( 45^\circ \) to a magnetic field of \( 0.1 \, \text{T} \). What is the force on the wire?

Q7. Two parallel wires \( 0.09 \, \text{m} \) apart carry \( 4 \, \text{A} \) and \( 5 \, \text{A} \) in opposite directions. What is the force per unit length? (\( \mu_0 = 4 \pi \times 10^{-7} \, \text{T m/A} \))

Q8. A solenoid has 700 turns per meter and carries a current of \( 2.8 \, \text{A} \). What is the magnetic field inside it? (\( \mu_0 = 4 \pi \times 10^{-7} \, \text{T m/A} \))

Q9. A long straight wire carries a current of \( 30 \, \text{A} \). What is the magnetic field at a distance of \( 0.3 \, \text{m} \) from it? (\( \mu_0 = 4 \pi \times 10^{-7} \, \text{T m/A} \))

Q10. A solenoid with 900 turns per meter carries \( 2 \, \text{A} \). What is the magnetic field inside? (\( \mu_0 = 4 \pi \times 10^{-7} \, \text{T m/A} \))