The electric field intensity produced by the radiation coming from a 100 W bulb at a distance of 3 m is E. The electric field intensity produced by the radiation coming from 60W at the same distance is $\sqrt {{x \over 5}}$E. Where the value of x = ____________.
Answer (integer)
3
Solution
$I = {1 \over 2}C{ \in _0}{E^2}$<br><br>${E^2} \propto I$<br><br>$I = {{Power} \over {Area}}$<br><br>${E^2} \propto {P \over A}$<br><br>$E \propto \sqrt P$<br><br>${{E'} \over E} = \sqrt {{{60} \over {100}}}$<br><br>$E' = \sqrt {{3 \over 5}} E$<br><br>So the value of x = 3
About this question
Subject: Physics · Chapter: Electromagnetic Waves · Topic: Properties of EM Waves
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