Q26.A source and a detector move away from each other in absence of wind with a speed of 20 m s−1 , with respect to the ground. If the detector detects a frequency of 1800 Hz of the sound coming from the source, then the original frequency of source considering the speed of sound in the air 340 m s−1 will be _____ Hz .
What This Question Tests
This question requires the application of the Doppler effect formula for sound waves when both the source and detector are moving away from each other.
Concepts Tested
Formulas Used
f' = f [(v - v_d) / (v + v_s)]
📚 NCERT Sections This Tests
11.8 — Light Of Frequency 7.21 × 1014 Hz Is Incident On A Metal Surface.
Physics Class 12 · Chapter 11
11.8 Light of frequency 7.21 × 1014 Hz is incident on a metal surface. Electrons with a maximum speed of 6.0 × 105 m/s are ejected from the surface. What is the threshold frequency for photoemission of electrons?
10.1 — Monochromatic Light Of Wavelength 589 Nm Is Incident From Air On A
Physics Class 12 · Chapter 10
10.1 Monochromatic light of wavelength 589 nm is incident from air on a water surface. What are the wavelength, frequency and speed of (a) reflected, and (b) refracted light? Refractive index of water is 1.33.
11.6 — The Threshold Frequency For A Certain Metal Is 3.3 × 1014 Hz. If Light
Physics Class 12 · Chapter 11
11.6 The threshold frequency for a certain metal is 3.3 × 1014 Hz. If light of frequency 8.2 × 1014 Hz is incident on the metal, predict the cut- off voltage for the photoelectric emission.
📋 Question Details
- Chapter
- Waves & Sound
- Topic
- Doppler Effect
- Year
- 2021
- Shift
- 26 Aug Shift 1
- Q Number
- Q26
- Type
- Numerical
- NCERT Ref
- Class 11 Physics Ch 15: Waves
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