Moving Charges and Magnetism

Number of turns, N=1200
Area of cross-section, A=5cm2=5×10−4m2
Magnetic moment, M=1.2JT−1
We are asked to find the current I.
Step 1: Formula for magnetic moment of a solenoid
A solenoid with N turns, cross-sectional area A, and current I has a magnetic moment:
M=NIA
Step 2: Substitute given values
1.2=1200×I×(5×10−4)
Step 3: Simplify
‌1.2=1200×5×10−4×I
‌1.2=(0.6)×I
Step 4: Solve for I
I=‌

1.2

0.6

=2A
Final Answer:
I=2A
Correct option: (B) 2 A