The ends of a coil, having 20 turns, area of cross-section 1 cm2 and resistance 2 Ω, are connected to a galvanometer of resistance 40 Ω. The plane of coil is inclined at an angle 30∘ to the direction of a magnetic field of intensity 1.5 T. The coil is quickly pulled out of the field, to a region of zero magnetic field. Calculate the total charge that passes through the galvanometer, during this interval.
A=1 cm2=10−4 m2
Total flux linked with the coil having turns N and area A is:
Initial flux, ϕ1=NBAcos60∘
When the coil is pulled out of the field, the flux becomes zero,
∴ Final flux, ϕ2=0
So, the change in flux is,
The charge flowed through circuit is:
∴ q=0.357×10−4C=35.7 μC
Hence, option (A) is the correct answer.
|Why this Question?
Short Trick: To solve these type of questions, we can use the following expression for charge flown,