The magnetic field within a long, straight solenoid with a circular cross-section of radius $r$ is (as shown) increasing at a rate of $\alpha$ .

The rate of change of flux through a circle with radius $a$ inside the solenoid, normal to the axis of the solenoid and with centre on the solenoid axis is

Question

The magnetic field within a long, straight solenoid with a circular cross-section of radius

r

is (as shown) increasing at a rate of

\alpha

.

The rate of change of flux through a circle with radius

a

inside the solenoid, normal to the axis of the solenoid and with centre on the solenoid axis is

Quantrex Academy · Accepted Answer

Correct answer: C. πa ^ 2 α

Rate of change of flux through circle with radius a (dϕm)/(dt) = A(dB)/(dt) = πa ^ 2 α

The magnetic field within a long, straight solenoid with a circular...