Question

Radio waves of constant amplitude can be generated with

• A. Rectifier
• B. Filter
• C. F.E.T
• D. Oscillator

Answer 1

The correct option is D

Oscillator

The explanation for the correct option:

Oscillator

1. Radio waves are electromagnetic radiation. An oscillator can be used to produce electromagnetic waves.
2. An oscillator operates on the oscillation principle. It converts DC signal to AC signal.
3. An oscillator generally generates a sine wave and square wave that has a constant amplitude throughout.

The explanation for the incorrect options:

A: Rectifier

1. A rectifier is an electrical device that is used to change alternating electricity into a direct current.
2. It is used for modulation and in voltage multipliers.
3. The amplitude during the rectification process varies.

B: Filter

1. As the name suggests the function of the filter is to pass the right signal and cancel out undesired signals.
2. During the process of filtration its amplitude varies.

C: FET

1. The Field effect transistor (FET) is a "voltage" controlled device because it uses the voltage supplied to its input terminal (known as the Gate) to regulate the current flowing from the source to the drain.
2. And its amplitude also varies.

Hence, option D is the correct answer.