CBSE
Two tunning forks A and B, produce notes of frequencies 258 Hz and 262 Hz. An unknown note sounded with A produces certain beats. When the same note is sounded with B. The beat frequency gets doubled. The unknown frequency is
250 Hz
252 Hz
254 Hz
256 Hz
A bat emitting an ultrasonic wave of frequency 2 x 104 Hz flies at a speed of 6 m/s between two parallel walls. The beat frequency between the two frequencies heard
by the bat is (Given, speed of sound is 330 m/s)
600 Hz
800 Hz
900 Hz
1300 Hz
Two sound waves with wavelengths 4 m and 5 m respectively each propagating in a gas with velocity 340 m/s. The number of beats per second will be
12 Hz
15 Hz
17 Hz
11 Hz
A stationary source emits a sound moving towards a wall with a velocity u. Speed of sound in air is v. The fractional change in the wavelength of the sound sent and the reflected sound is
In a wave motion y = A sin (kx - ωt), y can represent
electric field
magnetic field
displacement
pressure
Two strings with mass per unit length of 9 gcm-1 and 25 gcm-1 are joined together in series. The reflection coefficient for the vibration waves are
The equation of a simple harmonic wave is given by y = 3sin (50 t - x) where, x and y are in meters and t in seconds. The ratio of maximum particle velocity to the wave velocity is
2
The displacement y of a particle in a medium can be expressed as y =10-6 sin (l00t + 20x + / 4) m, where t is in second and x in metre. The speed of the wave is
2000 m/s
5 m/s
20 m/s
5 m/s
The equation of a wave is y = 5 sin where x is in cm and t in seconds. The maximum velocity of the wave will be
1 ms-1
2 ms-1
1.5 ms-1
1.25 ms-1
If the phase difference between two points is 60° on a wave velocity of 360 m/s and frequency 500 Hz, then path difference between the two points is
1 cm
6 cm
12 cm
24 cm