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The velocity of sound in hydrogen at $0 ° C$ is $1200 m s^{- 1}$ . When some amount of oxygen is mixed with hydrogen, the velocity decreases to $500 m s^{- 1}$ . The ratio of $H_{2}$ to $O_{2}$ by volume in this mixture is $\frac{256}{n}$ , given that the density of oxygen is $16$ times that of hydrogen. Write the value of $n$ .

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Important Questions on Waves

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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

ρ

and releases energy

E

, generating a spherical blast wave. The radius

R

of this blast wave varies with time

t

EASY

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

Two waves of sound of wavelength

1.2 m

and

1.25 m

in a medium produce

90

beats in

10 s .

The speed of sound in the medium is

MEDIUM

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}})

EASY

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

When sound travels from air to water the quantity that remains unchanged 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 velocity of sound in air is independent of change in

MEDIUM

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?

MEDIUM

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

It takes

2.0

seconds for a sound wave to travel between two fixed points when the day temperature is

10 ° C

. If the temperature rises to

30 ° C

, the sound wave travels between the same fixed parts in

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

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

The ratio of speed of sound in hydrogen gas to the speed of sound in oxygen gas at the same temperature is:

EASY

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

Sound travels fastest in

MEDIUM

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

Consider a wire with density

(d)

and stress

(σ) .

For the same density, if the stress increases

2

times, the speed of the transverse waves along the wire changes by

MEDIUM

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

MEDIUM

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

Let the speed of sound at

0 ° C

332 {m s}^{- 1}

. On a winter day sound travels

342 m

in one second. The atmospheric temperature on that day is

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:

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}

)

The velocity of sound in hydrogen at 0°C is 1200 m s-1. When some amount of oxygen is mixed with hydrogen, the velocity decreases to 500 m s-1. The ratio of H2 to O2 by volume in this mixture is 256n, given that the density of oxygen is 16 times that of hydrogen. Write the value of n.

Important Questions on Waves

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