The wavelengths of two sound waves in air are 81 173 m and 81 170 m . They produce 10 beats per second. Calculate the velocity of sound in air.

Here wavelength values are given as below λ 1 = 81 173 m = 0 . 468 m , λ 2 = 81 170 m = 0 . 476 m Δ n = 10 b e a t s Now using the below formula, we can calculate the velocity of sound in air Δ n = n 1 - n 2 Δ n = V λ 1 - V λ 2 Δ n = V 1 λ 1 - 1 λ 2 10 = V 173 81 - 170 81 10 = V 3 81 V = 10 × 81 3 V = 270 m / s

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Derive an expression of the speed of a longitudinal wave dimensionally.

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Physics>Oscillations and Waves>Waves>Speed of a Travelling Wave

If the particle starts its motion from mean position, the phase difference between displacement and acceleration is ____.

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Physics>Oscillations and Waves>Waves>Speed of a Travelling Wave

Consider a gas with molar mass

M .

If the sound at frequency

f

is introduced to a tube of this gas at temperature

T

then an internal acoustic standing wave is set up with nodes separated by

L .

The adiabatic constant

(γ = \frac{C_{p}}{C_{v}})

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Physics>Oscillations and Waves>Waves>Speed of a Travelling Wave

A bomb explodes at time

t = 0

in a uniform, isotropic medium of density

k = 1

and releases energy

E

, generating a spherical blast wave. The radius

R

of this blast wave varies with time

t

HARD

Physics>Oscillations and Waves>Waves>Speed of a Travelling Wave

Sound travels in a mixture of two moles of helium and

n

moles of hydrogen. If rms speed of gas molecules in the mixture is

\sqrt{2}

times the speed of sound, then the value of

n

will be

MEDIUM

Physics>Oscillations and Waves>Waves>Speed of a Travelling Wave

A tunning fork of frequency

480 H z

is used in an experiment for measuring speed of sound

(v)

in air by resonance tube method. Resonance is observed to occur at two successive lengths of the air column,

l_{1} = 30 c m

and

l_{2} = 70 c m .

Then,

ν

is equal to:

EASY

Physics>Oscillations and Waves>Waves>Speed of a Travelling Wave

When sound travels from air to water the quantity that remains unchanged is

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Physics>Oscillations and Waves>Waves>Speed of a Travelling Wave

A sound wave of frequency

200 Hz

is travelling in air. The speed of sound in the air is

340 m s^{- 1} .

What is the phase difference at a given instant between two points separated by a distance of

85 cm

along the direction of propagation?

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Physics>Oscillations and Waves>Waves>Speed of a Travelling Wave

An ideal gas is in thermodynamic equilibrium. The number of degrees of freedom of a molecule of the gas is

n

. The internal energy of one mole of the gas is

U_{n}

and the speed of sound in the gas is

v_{n}

. At a fixed temperature and pressure, which of the following is the correct option?

MEDIUM

Physics>Oscillations and Waves>Waves>Speed of a Travelling Wave

The pressure wave,

P = 0.01 \sin [1000 t - 3 x] N m^{- 2}

, corresponds to the sound produced by a vibrating blade on a day when atmospheric temperature is

0 ° C

. On some other day when temperature is

T

, the speed of sound produced by the same blade and at the same frequency is found to be

336 m s^{- 1}

. Approximate value of

T

is:

EASY

Physics>Oscillations and Waves>Waves>Speed of a Travelling Wave

Sound waves of wavelength

λ

and velocity

v

in medium-

1

enter medium-

2

. If their velocity in medium-

2

4 v

, the wavelength in medium-

2

EASY

Physics>Oscillations and Waves>Waves>Speed of a Travelling Wave

The distance between two consecutive points with phase difference of

60 °

in a wave of frequency

500 Hz

6.0 m

. The velocity with which wave is travelling is ______

km s^{- 1}

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Physics>Oscillations and Waves>Waves>Speed of a Travelling Wave

A heavy ball of mass

M

is suspended from the ceiling of a car by a light string of mass

m (m ≪ M) .

When the car is at rest, the speed of transverse waves in the string is

60 m s^{- 1}

. When the car has acceleration

a

, the wave-speed increases to

60.5 m s^{- 1}

. The value of

a

in terms of gravitational acceleration

g

is closed to:

EASY

Physics>Oscillations and Waves>Waves>Speed of a Travelling Wave

For a solid rod, the Young's modulus of elasticity is

3.2 \times 10^{11} N m^{- 2}

and density is

8 \times 10^{3} kg m^{- 3}

. The velocity of longitudinal wave in the rod will be

HARD

Physics>Oscillations and Waves>Waves>Speed of a Travelling Wave

The wavelengths of two sound waves in air are $\frac{81}{173} m$ and $\frac{81}{170} m$ . They produce $10$ beats per second. Calculate the velocity of sound in air.

EASY

Physics>Oscillations and Waves>Waves>Speed of a Travelling Wave

The equation of wave is given by

Y = 10^{- 2} \sin 2 π (160 t - 0.5 x + \frac{π}{4})

, where

x

and

Y

are in

m

and

t

s

. The speed of the wave is _______

km h^{- 1}

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Physics>Oscillations and Waves>Waves>Speed of a Travelling Wave

A string of length

1 m

and mass

5 g

is fixed at both ends. The tension in the string is

8 .0 N

. The string is set into vibration using an external vibrator of frequency

100 Hz

. The separation between successive nodes on the string is close to

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Physics>Oscillations and Waves>Waves>Speed of a Travelling Wave

A uniform rope of length

L

and mass

m_{1}

, hangs vertically from a rigid support. A block of mass

m_{2}

is attached to the free end of the rope. A transverse pulse of wavelength

λ_{1}

is produced at the lower end of the rope. The wavelength of the pulse when it reaches the top of the rope is

λ_{2}

. The ratio

\frac{λ_{2}}{λ_{1}}

is:

EASY

Physics>Oscillations and Waves>Waves>Speed of a Travelling Wave

A hospital uses an ultrasonic scanner to locate tumors in a tissue. The operating frequency of the scanner is

4.2 MHz .

The speed of sound in a tissue is

1.7 km / s .

The wavelength of sound in the tissue is

MEDIUM

Physics>Oscillations and Waves>Waves>Speed of a Travelling Wave

Consider a system of gas of a diatomic molecule in which the speed of sound at

0^{o} C

1260 m s^{- 1}

. Then, the molecular weight of the gas is in

g {mol}^{- 1}

, (given, the gas constant

R

8 .314 J {mol}^{- 1} K^{- 1}

)

EASY

Physics>Oscillations and Waves>Waves>Speed of a Travelling Wave

The percentage increase in the speed of transverse waves produced in a stretched string if the tension is increased by

4 %

, will be ___

%

Derive an expression of the speed of a longitudinal wave dimensionally.

Important Questions on Waves

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