Question

When the observer moves towards a stationary source with velocity '\(V_1\)', the apparent frequency of the emitted note is '\(F_1\)'. When the observer moves away from the source with velocity '\(V_1\)', the apparent frequency is '\(F_2\)'. If 'V' is the speed of sound in air and \(F_1/F_2 = 2\), then \(V/V_1 =\)

• A. \(2\)
• B. \(3\)
• C. \(6\)
• D. \(8\)

Hint:

Write apparent frequencies for approach and recession, then take the ratio.

Answer 1

The Correct Option is B

Step 1: Cross multiply:
$F_1 = 2F_2$ gives $V + V_1 = 2(V - V_1)$.

Step 2: Rearrange:
$3V_1 = V$.

Step 3: Answer:
$V/V_1 = 3$, option (B).

Final Answer:
The ratio V / V1 is 3. \[ \boxed{\text{(B) }3} \]