Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
MHT CET202620 April 2026Morning ShiftPhysicsWaves and SoundActual

A train is moving towards a stationary observer with speed 34 m/s. A train sounds a whistle of frequency 450 Hz. If the speed of sound is 340 m/s, the frequency heard by the observer in Hz is

Options

  1. A440
  2. B480
  3. C500
  4. D540

Correct answer

C. 500

Step-by-step solution

Using the Doppler effect formula for a source moving towards a stationary observer: f' = f ( v v - v_s ) Substituting the given values: f' = 450 ( 340 340 - 34 ) f' = 450 ( 340 306 ) f' = 450 10 9 f' = 500 Hz Answer: 500

Practice Waves and Sound on Quantrex Academy →

More from Waves and Sound

Resonance is produced between a turning fork and a resonance column tube with upper end open and lower end closed by water surface. If the frequency of the tuning fork is 800Hz, an 2026The speed of transverse wave in aluminium wire is 1 10 times the speed of longitudinal wave in the wire. The stress in the wire is (Young's Modulus of Al = 10¹⁰ Pa) 2026A source of frequency gives 6 beats/second when sounded with a source of frequency 200 Hz. The second Harmonic of frequency 2 of the source gives 8 beats/second when sounded with a 2026A sound wave of frequency 500 Hz travels between two points X and Y separated by a distance of 600 m in a time of 2 s. The number of waves between the points X and Y are 2025When both source of sound and observer approach each other with a speed equal to 10 % of the speed of sound, then the percentage change in frequency heard by the observer is nearly 2025The equation of a transverse wave propagating along a stretched string of length 80 cm is y =1.5 (5 10⁻³ x )+20 t , here ' x ' and ' y ' are in cm and the time ' t ' is in second. 2025If a travelling wave is given by y(x, t)=0.5 (70.1 x-10 t) , where x and y are in metre, the time t is in second, then the frequency of the wave is 2025In a closed organ pipe, the number of nodes formed in fifth and ninth harmonics are respectively 2025 Full Waves and Sound list All MHT CET PYQs