Question

Television frequencies are of the order of 100 MHz, while radio frequencies are of the order of 1 MHz. Using these as typical frequencies, the ratio of the emf generated in a loop antenna by a television wave to that generated by a radio wave, if both have equal electric field intensities, is

• A. 1
• B. 10
• C. 100
• D. 66.6

Hint:

The induced emf in a loop antenna is proportional to the frequency of the electromagnetic wave.

Answer 1

The Correct Option is C

The induced emf in a loop antenna is directly proportional to the frequency of the wave. Since both the electric field intensities are equal, the emf generated is proportional to the frequency of the wave. Therefore, the ratio of the emf generated by a television wave to that generated by a radio wave is the ratio of their frequencies: \[ \frac{f_{\text{tv}}}{f_{\text{radio}}} = \frac{100 \, \text{MHz}}{1 \, \text{MHz}} = 100 \] Thus, the correct answer is (C).