AP EAMCET · PHYSICS · Waves and Sound
A student holds a tuning fork oscillating at \(170 \mathrm{~Hz}\). He walks towards a wall at a constant speed of \(2 \mathrm{~ms}^{-1}\). The beat frequency observed by the student between the tuning fork and its echo is (Velocity of sound \(=340 \mathrm{~ms}^{-1}\) )
- A \(2.5 \mathrm{~Hz}\)
- B \(3 \mathrm{~Hz}\)
- C \(1 \mathrm{~Hz}\)
- D \(2 \mathrm{~Hz}\)
Answer & Solution
Correct Answer
(D) \(2 \mathrm{~Hz}\)
Step-by-step Solution
Detailed explanation
From Doppler's effect, apparent frequency, \(n^{\prime}=\left(\frac{v+v_0}{v-v_0}\right) n\) or, \(n^{\prime}=\left(\frac{340+2}{340-2}\right) \times 170\) or, \(\quad n^{\prime}=\frac{342}{338} \times 170\) or \(\quad n^{\prime}=172.01=172 \mathrm{~Hz}\) Therefore, beat…
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