Question

Figure shows a conducting loop being pulled out of a magnetic field with a speed v. Which of the four plots shown in figure (b) may represent the power delivered by the pulling agent as a function of the speed v?

Answer 1

(b) b

 

The emf developed across the ends of the loop is given by

`e=Bvl`

If R is the resistance of the loop, then the power delivered to the loop is given by

`P=e^2/R=(B^2v^2l^2)/R`

`rArr P prop v^2`

This relation is best represented by plot b in the figure.