Question

When source of sound moves towards a stationary observer, the wavelength of sound received by him

• A. decreases while frequency increases
• B. remains the same whereas frequency increases
• C. increases and frequency also increases
• D. decreases while frequency remains the same

Answer 1

The correct option is A decreases while frequency increases

As source of sound moves towards observer, the frequency increases . But the velocity of sound remains same.

And $\lambda =\frac{v}{f}$

Hence, $\lambda$ decreases.

Hence, answer is option-(A).