Q154 / 160 · TS EAMCET 2018 (05 May Shift 2) · Physics
An electromagnetic wave having frequency $4 \times 10^{14} \mathrm{~Hz}$ is passing through a small volume. The energy contained in this volume oscillates with frequency
- A$0 \mathrm{~Hz}$
- B$4 \times 10^{14} \mathrm{~Hz}$
- Correct answerC$8 \times 10^{14} \mathrm{~Hz}$
- D$2 \times 10^{14} \mathrm{~Hz}$
Solution
Frequency of an oscillation of energy with time is twice of frequency of electromagnetic wave.
$\begin{gathered}
\therefore f \text { (energy oscillations })=2 \times 4 \times 10^{24} \mathrm{~Hz} \\
=8 \times 10^{24} \mathrm{~Hz}
\end{gathered}$
Hence, the correct answer is option: 'C'.