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Standard XII

Physics

Capacitor in an AC Circuit

A circular pl...

Question

A circular plate of area $0.4 c m^{2}$ is kept at distance of 2m from isotropic(uniform in all directions) source of power $π$ W. Find the amount of energy received by plate in 5 secs.

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Solution

Energy emitted by speaker is $π J$

Energy will be transmitted in all directions that is in spherical shape
Therefore energy at 2m $E = \frac{π}{4 π r^{2}} = \frac{π}{4 π 2^{2}} = \frac{1}{16}$

Energy on the circular plate $E_{p} = 0.4 \times 10^{- 4} \times \frac{1}{16} = 2.5 \times 10^{- 8} J$

Energy fall in 5 sec $2.5 \times 10^{- 8} \times 5 = 12.5 \times 10^{- 6} J = 12.5 μ J$

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A circular plate of area 0.4cm2 is kept at distance of 2m from isotropic(uniform in all directions) source of power π W. Find the amount of energy received by plate in 5 secs.

Energy emitted by speaker is πJEnergy will be transmitted in all directions that is in spherical shapeTherefore energy at 2m E=π4πr2=π4π22=116Energy on the circular plate Ep=0.4×10−4×116=2.5×10−8JEnergy fall in 5 sec 2.5×10−8×5=12.5×10−6J=12.5μJ

A circular plate of area $0.4 c m^{2}$ is kept at distance of 2m from isotropic(uniform in all directions) source of power $π$ W. Find the amount of energy received by plate in 5 secs.