Science (English Medium) इयत्ता ११ - CBSE Question Bank Solutions for Physics

Two blocks of masses 400 g and 200 g are connected through a light string going over a pulley which is free to rotate about its axis. The pulley has a moment of inertia \[1 \cdot 6 \times  {10}^{- 4}   kg -  m^2\] and a radius 2⋅0 cm, Find (a) the kinetic energy of the system as the 400 g block falls through 50 cm, (b) the speed of the blocks at this instant.

The pulley shown in the following figure has a radius of 20 cm and moment of inertia 0⋅2 kg-m². The string going over it is attached at one end to a vertical spring of spring constant 50 N/m fixed from below, and supports a 1 kg mass at the other end. The system is released from rest with the spring at its natural length. Find the speed of the block when it has descended through 10 cm. Take g = 10 m/s².

When we clap our hands, the sound produced is best described by Here p denotes the change in pressure from the equilibrium value.

A tuning fork sends sound waves in air. If the temperature of the air increases, which of the following parameters will change?

When sound wave is refracted from air to water, which of the following will remain unchanged?

Two sound waves move in the same direction in the same medium. The pressure amplitudes of the waves are equal but the wavelength of the first wave is double the second. Let the average power transmitted across a cross section by the first wave be P₁ and that by the second wave be P₂. Then

When two waves with same frequency and constant phase difference interfere,

A tuning fork of frequency 512 Hz is vibrated with a sonometer wire and 6 beats per second are heard. The beat frequency reduces if the tension in the string is slightly increased. The original frequency of vibration of the string is

A small source of sounds moves on a circle as shown in figure and an observer is sitting at O. Let \[v_1, v_2,    v_3\] be the frequencies heard when the source is at A, B and C respectively.

When you speak to your friend, which of the following parameters have a unique value in the sound produced?

An electrically maintained tuning fork vibrates with constant frequency and constant amplitude. If the temperature of the surrounding air increases but pressure remains constant, the produced will have

(a) larger wavelength
(b) larger frequency
(c) larger velocity
(d) larger time period.

The fundamental frequency of a vibrating organ pipe is 200 Hz.

(a) The first overtone is 400 Hz.
(b) The first overtone may be 400 Hz.
(c) The first overtone may be 600 Hz.
(d) 600 Hz is an overtone.

A source of sound moves towards an observer.

A listener is at rest with respect to the source of sound. A wind starts blowing along the line joining the source and the observer. Which of the following quantities do not change?
(a) Frequency
(b) Velocity of sound
(c) Wavelength
(d) Time period

A steel tube of length 1.00 m is struck at one end. A person with his ear closed to the other end hears the sound of the blow twice, one travelling through the body of the tube and the other through the air in the tube. Find the time gap between the two hearings. Use the table in the text for speeds of sound in various substances.

A man stands before a large wall at a distance of 50.0 m and claps his hands at regular intervals. Initially, the interval is large. He gradually reduces the interval and fixes it at a value when the echo of a clap merges every 3 seconds, find the velocity of sound in air.

A person can hear sound waves in the frequency range 20 Hz to 20 kHz. Find the minimum and the maximum wavelengths of sound that is audible to the person. The speed of sound is 360 m s⁻¹.

Find the minimum and maximum wavelengths of sound in water that is in the audible range (20−20000 Hz) for an average human ear. Speed of sound in water = 1450 m s⁻¹.