JEE Main2013PhysicsElectromagnetic InductionActual
A metallic rod of length l is tied to a string of length 2 l and made to rotate with angular speed ω on a horizontal table with one end of the string fixed. If there is a vertical magnetic field B in the region, the e.m.f. induced across the ends of the rod is:
Options
- A4 B ω l 2 2
- B5 B ω l 2 2
- C2 B ω l 2 2
- D3 B ω l 2 2
Correct answer
B. 5 B ω l 2 2
Step-by-step solution
e = ∫ 2 l 3 l B V d x e = ∫ 2 ℓ 3 ℓ B(ωx)dx e = ω B ∫ 2 l 3 l x d x e = ω B x 2 2 2 l 3 l e = ω B 2 3 l 2 - 2 l 2 2 l 3 l e = 5 2 ω B l 2