Question

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


A. `A` to `B` and `C` to `D`
B. `B` to `A` and `D` to `C`
C. `c`
D. `d`

Answer 1

Correct Answer - B
Induced emf `=Bvl`
Induced current `i=(Bvl)/(R)`
Magnetic force on loop `F_(m)=Bil=(B^(2)vl^(2))/(R)`
Since loop is moving with constant speed
`F=F_(m)`
Input power `P=vec(F).vec(v)=Fv=(B^(2)v^(2)l^(2))/(R)`
`Pv//s` graph: `ypropx^(2)` (parabola, open upward)