The magnetic flux through a circuit of resistance R changes by an amount $∆\varphi$ in a time ∆t. Then the total quantity of electric charge Q that passes any point in the circuit during the time ∆t is represented by:

1. $\mathrm{Q}=\frac{\mathrm{\Delta }\varphi }{\mathrm{R}}$

2. $\mathrm{Q}=\frac{\mathrm{\Delta }\varphi }{\mathrm{\Delta t}}$

3. $\mathrm{Q}=\mathrm{R}\cdot \frac{\mathrm{\Delta }\varphi }{\mathrm{\Delta t}}$

4. $\mathrm{Q}=\frac{1}{\mathrm{R}}\cdot \frac{\mathrm{\Delta }\varphi }{\mathrm{\Delta t}}$

As a result of a change in the magnetic flux linked to the closed-loop shown in the figure, an e.m.f., V volt is induced in the loop. The work done (joules) in taking a charge Q coulomb once along the loop is:

1. QV

2. QV/2

3. 2QV

4. zero