JEE Main 2022 · 25 Jun · Shift 1 · Physics Q42

← JEE Main 2022 · 25 Jun · Shift 1

PhysicsSingle correct+4 / -1Question 42 of 90

The electric field in an electromagnetic wave is given by $E=56.5\sin\omega(t-x/c)\ \mathrm{NC^{-1}}$ . Find the intensity of the wave if it is propagating along $x$ -axis in the free space.

(Given $\varepsilon_0=8.85\times10^{-12}\ \mathrm{C^2N^{-1}m^{-2}}$ )

5.65\ \mathrm{Wm^{-2}}

4.24\ \mathrm{Wm^{-2}}

1.9\times10^{-7}\ \mathrm{Wm^{-2}}

56.5\ \mathrm{Wm^{-2}}

Answer and worked solution

Official answer: B

Intensity. $I=\frac12\varepsilon_0cE_0^2=\frac12(8.85\times10^{-12})(3\times10^8)(56.5)^2\approx4.24$ W m $^{-2}$ .

(B)

Topics:Energy and momentum of EM waves

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JEE Main 2022 · 25 Jun · Shift 1, Physics question 42