NEET Magnetic Effects of Current and Magnetism — Set 2

Question 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} $)

Accepted Answer

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} $.

Question 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} $)

Accepted Answer

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} $.

Question 3

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} $)

Accepted Answer

$ 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} $.

NEET Physics: Magnetic Effects of Current and Magnetism — Practice Set 2

Q1. A solenoid with 1500 turns per meter carries a current of \( 4 \, \text{A} \). What is the magnetic field inside the solenoid? (\( \mu_0 = 4 \pi \times 10^{-7} \, \text{T m/A} \))

Q2. 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? (\( \mu_0 = 4 \pi \times 10^{-7} \, \text{T m/A} \))

Q3. Two parallel wires \( 0.02 \, \text{m} \) apart carry \( 5 \, \text{A} \) each in opposite directions. What is the force per unit length? (\( \mu_0 = 4 \pi \times 10^{-7} \, \text{T m/A} \))

Q4. 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?

Q5. Why does a charged particle describe a circular path when moving perpendicular to a uniform magnetic field?

Q6. 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?

Q7. 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?

Q8. What is the SI unit of magnetic field strength?

Q9. 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?

Q10. 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?