JEE Mains · Physics · STD 12 - 8. Electromagnetic waves
A lamp emits monochromatic green light uniformly in all directions. The lamp is \(3\%\) efficient in converting electrical power to electromagnetic waves and consumes \(100\,W\) of power . The amplitude of the electric field associated with the electromagnetic radiation at a distance of \(5\,m\) from the lamp will be nearly.......\(V/m\)
- A \(1.34\)
- B \(2.68\)
- C \(4.02\)
- D \(5.36 \)
Answer & Solution
Correct Answer
(B) \(2.68\)
Step-by-step Solution
Detailed explanation
Wavelength of monochromatic green light \(=5.5 \times 10^{-5} \mathrm{cm}\) Intensity \(I\,=\,\frac{\text { Power }}{\text { Area }}\) \( = \frac{{100 \times (3/100)}}{{4\pi {{(5)}^2}}}\) \(=\frac{3}{100 \pi} \mathrm{Wm}^{-2}\) Now, half of this intensity ( \(\mathrm{I}\) )…
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