Suppose that intensity of a laser is ${{315} \over \pi }$ W/m2.
The rms electric field, in units of V/m associated
with this source is close to the nearest integer is __________.
$\in$0 = 8.86 × 10–12 C2 Nm–2; c = 3 × 108 ms–1)
Answer (integer)
194
Solution
I = ${1 \over 2}$$\varepsilon$<sub>0</sub>$E_0^2$c
<br><br>$\Rightarrow$ E<sub>0</sub> = $\sqrt {{{2I} \over {{\varepsilon _0}c}}}$
<br><br>$\therefore$ E<sub>rms</sub> = ${{{E_0}} \over {\sqrt 2 }}$ = $\sqrt {{I \over {{\varepsilon _0}c}}}$
<br><br>= $$\sqrt {{{{{315} \over \pi }} \over {8.86 \times {{10}^{ - 12}} \times 3 \times {{10}^8}}}} $$
<br><br>= 194
About this question
Subject: Physics · Chapter: Electromagnetic Waves · Topic: Properties of EM Waves
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