1.

An e.m.f. `E =E_(0) cos omega t` is applied to a circuit containing L and R in series. If `X_(L)=R`, then the power dissipated in the circuit is given byA. `(E_(0)^(2))/(8R)`B. `(E_(0)^(2))/(4R)`C. `(E_(0)^(2))/(2R)`D. `(E_(0)^(2))/(R)`

Answer» Correct Answer - B
`E= E_(0) cos omega t`
Power = `(E_(0)I_(0)cos theta)/(2) = (E_(0))/2 (E_0)/z xx R/z`
`= (E_(0)^(2)R)/(2 z^(2)) = (E_(0)^(2)R)/(2sqrt(R^(2)+R^(2))^(2))) = (E_(0)^(2)R)/(2 xx 2R^(2)) = (E_(0)^(2))/(4R)`.


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