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A light ray is incident on a rotating mi...

A light ray is incident on a rotating mirror, which is rotating with angular speed `3rad//s` as shown in figure. The speed of bright spot on the wall when `theta=30^(@)`

Text Solution

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The correct Answer is:
8
`tan(2theta-90)=Y/L`
`y=-Lcot2theta`
`(dy)/(dt)=-Lxx(-cosec^(2) 2theta)xx2 (d theta)/(dt)`
`=2L(cosec^(2) 2theta)(d theta)/(dt)`
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