Electromagnetic Waves

JEE Main level, single correct, medium

156 of 165

Question 156 of 165

If a source of power 4 kW4 \mathrm{~kW} produces 102010^{20} photons/second, the radiation belong to a part of the spectrum called

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Answer: (A) X-rays

4×103=1020xhff=4×1031020×6.023×10−34f=6.03×1016 Hz\begin{aligned} & 4 \times 10^3=10^{20} \mathrm{xhf} \\ & f=\frac{4 \times 10^3}{10^{20} \times 6.023 \times 10^{-34}} \\ & f=6.03 \times 10^{16} \mathrm{~Hz} \end{aligned}
The obtained frequency lies in the band of X-rays.

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