Question

If magnetic flux changes by \[\Delta\Phi_B\] in a time interval \[\Delta t\], which expression gives the induced emf \[e\]?

Options

• \[e=-\frac{\Delta t}{\Delta\Phi_B}\]

• \[e=\frac{\Delta\Phi_B}{\Delta t}\]

• \[e=-\frac{\Delta\Phi_B}{\Delta t}\]

• \[e=-\Delta\Phi_B\Delta t\]

Answer 1

If ΔΦ_B​ is the change in magnetic flux in a time interval Δt, then the induced emf e is given by:

e = \[-\frac{\Delta\Phi_B}{\Delta t}\]

The change in magnetic flux is divided by the time interval to obtain its rate of change. The negative sign gives the direction specified by Lenz’s law.