Tag: physics

Quizzes (598) Questions (13441)

Questions Related to physics

Multiple choice physics study of sound sound as a wave of disturbance vibrations in a tuning fork vibrations in tuning fork

A uniform tub to length $60.5\,cm$ is held vertically with its lower end dipped in water. A sound source of frequency $500\,Hz$ sends sound waves into the tube. When it is $50\,cm$, the tube resonates with the source of sound. Two lowest frequencies (in Hz), to which tube will resonate when it is taken out of water, are (approximately)

  1. $281, 562$
  2. $281, 843$
  3. $276, 522$
  4. $272, 544$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

When the tube is taken out of water, it acts as an open pipe of length L = 0.605 m. The fundamental frequency is f = v / (2L). Using the resonance data (50 cm length, 500 Hz source), the speed of sound is v = 4 * f * L_res = 4 * 500 * 0.5 = 1000 m/s. The fundamental frequency of the open pipe is 1000 / (2 * 0.605) = 826 Hz, which does not match the options well, suggesting a potential calculation error in the source question or specific assumptions about the end correction.

Multiple choice physics study of sound sound as a wave of disturbance vibrations in a tuning fork vibrations in tuning fork

If wind blows in a direction opposite to the sound propagation, then the velocity of the sound

  1. increases

  2. decreases

  3. remains constant

  4. Cannot be determined
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

When wind blows in the direction opposite to sound propagation, the effective velocity of the sound wave relative to the ground decreases. This is a standard application of the principle of relative velocity for waves in a moving medium.

Multiple choice physics study of sound sound as a wave of disturbance vibrations in a tuning fork vibrations in tuning fork

A replica of longitudinal waves can be best observed 

  1. by swinging a pendulum

  2. by pressing and releasing a horizontal spring

  3. by striking a guitar string

  4. by rotating a top
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

If we press and release a horizontal spring, it exhibits a confined motion of compression and rarefaction. So, it shows a replica of longitudinal waves. A swinging pendulum performs simple harmonic motion. A struck guitar string exhibits a replica of transverse waves. A rotating top exhibits rotational motion.

Multiple choice physics study of sound sound as a wave of disturbance vibrations in a tuning fork vibrations in tuning fork

Sound waves in air are

  1. transverse

  2. longitudinal

  3. electromagnetic

  4. polarised
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Sound waves are longitudinal waves because the disturbance of the medium particles is parallel to the direction of propagation of wave. The compression and rarefraction pulses produced moves in the direction parallel to the propagation direction of wave.

Multiple choice physics study of sound sound as a wave of disturbance vibrations in a tuning fork vibrations in tuning fork

A tuning fork is excited by striking it with a padded hammer. What would be the nature of the vibrations executed by the prongs as well as the stem of the fork respectively ? (The reference direction is that of the propagation of the sound wave.)

  1. Both vibrate longitudinally

  2. Both vibrate transversely

  3. The prong vibrate longitudinally whereas the stem vibrates transversely

  4. The prong vibrate transversely whereas the stem vibrates longitudinally
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

When a tuning fork is struck, the prongs vibrate transversely (perpendicular to the length of the prong). The stem, which is connected to the base of the prongs, vibrates longitudinally (along the axis of the stem) to transmit the sound to the resonance box.

Multiple choice physics propagation of sound waves sound as a wave of disturbance vibrations in a tuning fork vibrations in tuning fork

The ratio of the speed of a body to the speed of sound is called:

  1. Mach number

  2. Doppler Ratio

  3. Sonic index

  4. Refractive index
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Mach number of a body is the ratio of its speed to that of local sound.
The local speed of sound, and thereby the Mach number, depends on the condition of the surrounding medium, in particular the temperature and pressure. The Mach number is primarily used to determine the approximation with which a flow can be treated as an incompressible flow. 

Multiple choice physics vibrations of stretched strings sound as a wave of disturbance vibrations in a tuning fork vibrations in tuning fork

Which type of wave is produced in the stem of tuning fork?

  1. transverse

  2. transverse stationary

  3. longitudinal

  4. longitudinal stationary
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

When tuning fork is sounded by striking its one end on rubber pad then the prongs vibrate in and out and stem vibrate up and down. Hence, vibration of prongs are transverse and those of stem are longitudinal.