A metal rod of resistance `20Omega` is fixed along diameter of a conducting ring of radius 0.1m and on x-y plane. There is a magnetic field B=(50t) . The ring roatates with an angular velocity `omega=20rad//s` about its axis. An external resistance resistance `10Omega` is connected cross the centre of the ring an rim. The current through external resistance is

Options

A. (a) `(1)/(4)`
B. (b) `(1)/(2)`
C. ( c) `(1)/(3)`
D. (d) `0`

Answer

C

Explanation

(c ) emf induced between centre of the ring and the rim is
`e = (1)/(2)BomegaR^(2) = (1)/(2)(50)(20)(0.1)^(2) = 5V`

Now the cicuit can be drawn as follows:

``:.` I = (5) + (10 + 5) = (1)/(3)A`