Question:
A source of sound of frequency \(500\ \text{Hz}\) is moving towards an observer with velocity \(30\ \text{m/s}\). The speed of sound is \(330\ \text{m/s}\). The frequency heard by the observer will be
A source of sound of frequency \(500\ \text{Hz}\) is moving towards an observer with velocity \(30\ \text{m/s}\). The speed of sound is \(330\ \text{m/s}\). The frequency heard by the observer will be
Show Hint
When source moves towards observer, apparent frequency increases; use denominator \(v-v_s\).
Updated On: May 7, 2026
- \(450\ \text{Hz}\)
- \(550\ \text{Hz}\)
- \(600\ \text{Hz}\)
- \(500\ \text{Hz}\)
Show Solution
Verified By Collegedunia
The Correct Option is B
Solution and Explanation
Concept:
When a source moves towards a stationary observer, apparent frequency increases and is given by:
\[
f' = f\left(\frac{v}{v-v_s}\right)
\]
where \(v\) is speed of sound and \(v_s\) is speed of source.
Step 1: Given: \[ f=500\ \text{Hz} \] \[ v=330\ \text{m/s} \] \[ v_s=30\ \text{m/s} \]
Step 2: Apply Doppler effect formula. \[ f'=500\left(\frac{330}{330-30}\right) \] \[ f'=500\left(\frac{330}{300}\right) \] \[ f'=500\left(\frac{11}{10}\right) \] \[ f'=550\ \text{Hz} \] Therefore, \[ \boxed{550\ \text{Hz}} \]
Step 1: Given: \[ f=500\ \text{Hz} \] \[ v=330\ \text{m/s} \] \[ v_s=30\ \text{m/s} \]
Step 2: Apply Doppler effect formula. \[ f'=500\left(\frac{330}{330-30}\right) \] \[ f'=500\left(\frac{330}{300}\right) \] \[ f'=500\left(\frac{11}{10}\right) \] \[ f'=550\ \text{Hz} \] Therefore, \[ \boxed{550\ \text{Hz}} \]
Was this answer helpful?
0
0
Top AP ECET Physics Questions
- Three rods of same dimensions have thermal conductivities 3 K, 2 K and K. They are arranged as shown below:What will be the temperature T of the junction?
- A ball of mass 0.6 kg attached to a light inextensible string rotates in a vertical circle of radius 0.75 m such that it has a speed of $ 5\text{ }m{{s}^{-1}} $ when the string is horizontal. Tension in string when it h horizontal on other side is $ (g=10m{{s}^{-}}2) $
- Three resistances of equal values are arranged in four different configurations as shown below. Power dissipation in the increasing order is
- Four resistors $A, B, C$ and $D$ form a Wheatstones bridge. The bridge is balanced, when $C=100 \Omega$. If $A$ and $B$ are interchanged, the bridge balances for $C=121 \Omega$. The value of $D$ is
- A parallel plate capacitor consists of two circular plates each of radius $2 \,cm$, separated by a distance of $0.1 \,mm$. If the potential difference across the plates is varying at the rate of $5 \times 10^{6} Vs ^{-1}$, then the value of displacement current is
View More Questions
Top AP ECET Sound Wave Questions
- The beats are produced by two sound sources of same amplitude and of nearly equal frequencies. The maximum intensity of beats will be {
- A siren emitting sound of frequency \(800\text{ Hz}\) is going away from a static listener with a speed of \(30\text{ m/s}\). Frequency of sound heard by the listener is \((\text{Velocity of sound in air}=340\text{ m/s})\)
- Two identical piano wires, when tuned to a fundamental frequency of \(400\ \text{Hz}\), produce no beats. One wire is then slightly tightened, and the beat frequency heard is \(2\ \text{Hz}\). What is the new fundamental frequency of the tightened wire?
- In acoustics, βNoiseβ is generally characterized by
- If the volume of a room is doubled and the total absorption is halved, the reverberation time will
View More Questions
Top AP ECET Questions
- The sum of the four digit even numbers that can be formed with the digits 0,3,5,4 with out repetition is
- Thermal decomposition of $HCOOH$ is a first order reaction and the rate constant at T(K) is $4.606 \times 10^{-3}\, s^{-1}$. The time required to decompose $90\%$ of initial quantity of $HCOOH$ at $T(K)$ in seconds is
- Three rods of same dimensions have thermal conductivities 3 K, 2 K and K. They are arranged as shown below:What will be the temperature T of the junction?
- To which group and period does the element belong if the electronic configuration of an element in its $-2$ oxidation state is $1s^{2} 2s^{2} 2p^{6} 3s^{2} 3p^{6}$ ?
- A ball of mass 0.6 kg attached to a light inextensible string rotates in a vertical circle of radius 0.75 m such that it has a speed of $ 5\text{ }m{{s}^{-1}} $ when the string is horizontal. Tension in string when it h horizontal on other side is $ (g=10m{{s}^{-}}2) $
View More Questions