Question

A carrier wave of peak voltage \(60\,\text{V}\) is used to transmit a message signal. Then the peak voltage of the modulating signal in order to have a modulation index of \(90\%\) is

• A. \(30\,\text{V}\)
• B. \(54\,\text{V}\)
• C. \(45\,\text{V}\)
• D. \(60\,\text{V}\)

Hint:

In amplitude modulation, \[ m=\frac{V_m}{V_c}. \] For proper transmission without distortion, \[ 0\le m\le 1. \] If \(m>1\), over-modulation occurs and the received signal becomes distorted.

Answer 1

The Correct Option is B

Step 1: Compare radii of curvature for different particles.
Radius in magnetic field: r = mv/(qB). α-particles have large mass (4u) so large r (small deflection). β-particles (electrons) have tiny mass so small r (large deflection). γ-rays and neutrons have q=0 so no deflection at all.

Step 2: Final Answer:
Maximum deflection is shown by stream of β-particles (option 2).