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a semicircle wire of radius R is rotated...

a semicircle wire of radius `R` is rotated with constant angular velocity about an axis passing through one end and perpendicular to the plane of wire. There is a uniform magnetic field of strength `B`. The induced emf between the ends is

A

(a) `BomegaR^(2)//2`

B

(b) `2BomegaR^(2)`

C

( c) is variable

D

(d) none of these

Text Solution

Verified by Experts

The correct Answer is:
B
(b) We connect a conducting wire from `A` to `C` and complete the semicircular loop.
The emf in the semicircular loop is zero because its magnetic flux does not change.
`:.` Emf of section `APC + emf of section CQA = 0`
`:.` Emf of section `APC = emf of section AQC = 2BR^(2) omega`
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