A radiation is emitted by $$1000$$ W bulb and it generates an electric field and magnetic field at P, placed at a distance of $$2$$ m. The efficiency of the bulb is $$1.25$$%. The value of peak electric field at P is x×$$10$$−$$1V/m$$ . Value of x is $$_______$$. (Round-off$$ to the nearest $$integer) [Take ε$$0=8.85$$×$$10$$−$$12C2N$$−$$1m$$−$$2$$,$$c=3$$×$$108ms$$−$$1$$ ]

Question

A radiation is emitted by $$1000$$ W bulb and it generates an electric field and magnetic field at P, placed at a distance of $$2$$ m. The efficiency of the bulb is $$1.25$$%. The value of peak electric field at P is x×$$10$$−$$1V/m$$ . Value of x is $$_______$$. (Round-off$$ to the nearest $$integer) [Take ε$$0=8.85$$×$$10$$−$$12C2N$$−$$1m$$−$$2$$,$$c=3$$×$$108ms$$−$$1$$ ]

Infinity Learn · Accepted Answer

Intensity $$=l=P4$$$$π$$$$r2=12$$ε$$0E02c$$⇒$$1.25100$$×$$10004$$π×$$4=128.85$$×$$10$$−$$12$$×$$E02$$×$$3$$×$$108$$⇒$$E02=187.2538$$⇒$$E0=13.68=136.8$$×$$10$$−$$1V/m$$⇒x≃$$137$$

Electromagnetic waves and its nature

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Electromagnetic waves and its nature

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Intensity =l=P4πr2=12ε0E02c⇒1.25100×10004π×4=128.85×10−12×E02×3×108⇒E02=187.2538⇒E0=13.68=136.8×10−1V/m⇒x≃137

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