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JEE Main 2024 (6 Apr, Shift 2) · Energy Density & Intensity

Energy Density & Intensity question from JEE Main 2024 (6 Apr, Shift 2)

Q6JEE Main 2024 · 6 APR · SHIFT 2Easy

Energy Density & Intensity

In the given electromagnetic wave Ey=600sin⁡(ωt−kx) V m−1E_y = 600 \sin(\omega t - kx)\text{ V m}^{-1}, intensity of the associated light beam is (in W/m2\text{W/m}^2): (Given ϵ0=9×10−12 C2 N−1 m−2\epsilon_0 = 9 \times 10^{-12}\text{ C}^2\text{ N}^{-1}\text{ m}^{-2})

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Answer: (a)

  1. I=12ε0cE02I = \tfrac{1}{2}\varepsilon_0 c E_0^2
  2. I=12×9×10−12×3×108×6002=1.35×10−3×3.6×105I = \tfrac{1}{2} \times 9 \times 10^{-12} \times 3 \times 10^{8} \times 600^2 = 1.35 \times 10^{-3} \times 3.6 \times 10^{5}
  3. I=486I = 486 W/m2^2
  4. So the answer is (a) 486.
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