QJEEM20Ph18fa: JEE Main 2020 Physics - Class 12 JEEM20Ph18fa Solution: Suppose that intensity of a laser is 315 π W/m 2 . The rms…

Question

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Suppose that intensity of a laser is

\frac{315}{π}

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)

Accepted Answer

I =

\frac{1}{2}

ε

₀

E_{0}^{2}

c

\Rightarrow

E₀ =

\sqrt{\frac{2 I}{ε_{0} c}}

∴

E_rms =

\frac{E_{0}}{\sqrt{2}}

=

\sqrt{\frac{I}{ε_{0} c}}

=

\sqrt{\frac{\frac{315}{π}}{8.86 \times 10^{- 12} \times 3 \times 10^{8}}}

= 194

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