Given below are two statements
Statement I: For transmitting a signal, size of antenna ( ) should be comparable to wavelength of signal (at least in dimension).
Statement II: In amplitude modulation, amplitude of carrier wave remains constant (unchanged).
In the light of the above statements, choose the most appropriate answer from the options given below.
Statement I: For transmitting a signal, size of antenna ( ) should be comparable to wavelength of signal (at least in dimension).
Statement II: In amplitude modulation, amplitude of carrier wave remains constant (unchanged).
In the light of the above statements, choose the most appropriate answer from the options given below.
- (A)Both Statement I and Statement II are correct
- (B)Both Statement I and Statement II are incorrect
- (C)Statement I is incorrect but Statement II is correct
- (D)Statement I is correct but Statement II is incorrect✓ Correct
Answer: (D)
Solution
An antenna radiates efficiently only when its physical size is comparable to the wavelength of the signal it carries, the usual working requirement being a length of at least a quarter of the wavelength, so the first statement holds. In amplitude modulation the amplitude of the carrier is deliberately made to vary in step with the message signal, and it is this changing envelope that carries the information, so the claim that the carrier amplitude stays unchanged is false. Hence the first statement is correct while the second is incorrect.
JEE Main · 2023 · 31 Jan 2023 · Shift 2 · Single correct option