Which of the following represent a correct block diagram of a radio r…

The correct answer is Option (2)

In a radio receiver the signal is processed in a fixed order: the tuner selects the wanted station, the radio-frequency (RF) amplifier strengthens the weak modulated signal, the detector recovers the audio signal from the carrier, and the audio-frequency (AF) amplifier strengthens it before it drives the loudspeaker.

The detector must come after the RF stage, because the signal at the antenna is too weak to be detected, and the AF amplifier must come after the detector, because the audio signal exists only after detection. Only the second arrangement follows this order.

Note: This question is from the pre-rationalised NCERT book (2022-23). The topic was removed from the latest NCERT book (2026-27), and it also appears to be out of the CUET 2026 syllabus.

NCERT (Pre-rationalised edition, 2022-23):
Detection of Amplitude Modulated Wave – “… The transmitted message gets attenuated in propagating through the channel. The receiving antenna is therefore to be followed by an amplifier and a detector. In addition, to facilitate further processing, the carrier frequency is usually changed to a lower frequency by what is called an intermediate frequency (IF) stage preceding the detection. The detected signal may not be strong enough to be made use of and hence is required to be amplified. A block diagram of a typical receiver is shown in Fig. 15.12”