Sound waves travel at 350 m/s through warm air and at 3,500 m/s through brass. What happens to the wavelength of a 700 Hz acoustic wave as it enters brass from warm air?

A sound wave with frequency f travels through air at speed v. With what speed will a sound wave with frequency 4f travel through the air?

A

v/4

B

v

C

2v

D

4v

Ultrasonic waves of frequency 3 × 10⁵ Hz are passed through a medium, where speed of sound is 10 times that in air (speed of sound in air is 300 m/s). The wavelength of this wave in that medium will be of the order of

A

1 cm

B

10 cm

C

100 cm

D

0.1 cm

Consider the following statements.
1. In sound waves, the vibrations are perpendicular to the direction in which the wave travels.
2. Sound waves are elastic waves.
Which of the statement(s) given above is/are correct?

A

Only 2

B

Only 1

C

Both 1 and 2

D

Neither 1 nor 2

Which of the statements given above are correct?
1. P - waves are the first seismic waves to reach a place
2. S - waves travel only through liquids
3. Arrival time of P and S - waves is used to locate the epicentre
4. Richter scale is a logarithmic scale

A

1, 2 and 3

B

1, 3 and 4

C

1 and 4

D

3 and 4

Statement I Sound waves can travel through vacuum.
Statement II Light is an electromagnetic wave and can travel through vacuum.

A

Both the statements are true and statement II is the correct explanation of statement I

B

Both the statements are true, but statement II is not the correct explanation of statement I

C

Statement I is true, but statement II is false

D

Statement I is false, but statement II is true

A sound wave has a frequency of 4 kHz and a wavelength of 40 cm. The time taken by the sound wave to travel a distance of 3.2 km is

A

0.5 s

B

2.0 s

C

4.0 s

D

1.0 s

In two types of brass, the ratios of Copper to Zinc are 8:3 and 15:7 respectively. If the two types of brass be melted and mixed in the ratio 5:2 a new typeof brass is obtained. The ratio of Copper to Zinc in this new type of brass is

A

3:2

B

2:3

C

3:4

D

5:2

Which of the following statement(s) about electromagnetic waves, sound waves and water waves is/are correct?
1. They exhibit reflection.
2. They carry energy.
3. They exert pressure.
4. They can travel in vacuum.

A

1, 2 and 3

B

2 and 4

C

1 and 3

D

Only 1

Statement I Sound waves cannot propagate in vacuum.
Statement II Sound waves are elastic waves and require a medium to propagate.

A

Both the statements are true and statement II is the correct explanation of statement I

B

Both the statements are true, but statement II is not the correct explanation of statement I

C

Statement I is true, but statement II is false

D

Statement I is false, but statement II is true

A free particle with energy E whose wave function is a plane wave with wavelength λ enters a region of constant potential V > 0, where the wavelength of the particle is 2λ. The ratio (V/E) is

A

$$\frac{1}{2}$$

B

$$\frac{2}{3}$$

C

$$\frac{3}{4}$$

D

$$\frac{4}{5}$$