Practice MCQ Questions and answers on Physics-GK

21

Which is a correct way to measure wavelength?

A) Nearest peak to peak B) Nearest peak to nearest trough C) Nearest trough to peak D) None of the above

Discuss

Answer & Solution

Answer: Option A

Solution:

Wavelength of a wave can be measured with the distance between two nearest crest and crest or nearest troughs. It is measured as armstrong units.

22

If the phase difference between two points is 120° for a wave with velocity of 360 m/s and frequency 500 Hz, then path difference between the two points is

A) 1 cm B) 6 cm C) 12 cm D) 24 cm

Discuss

Answer & Solution

Answer: Option D

Solution:

If v is the wave velocity and f is the frequency, wavelength is given by:
λ = v/f
So as per the question,
λ = 360/500 = 0.72
The path difference between two points is given by
λ/2π × φ = 0.72/360 × 120
= 0.24 m
= 24 cm

23

Why are we able to hear short wave broadcasts better than long wave broadcasts ?

A) Short waves are more energetic than long waves. B) Short waves are unaffected by atmospheric disturbances. C) Short wave broadcasts are made by nearby radio stations. D) By convention, short waves are meant for long distances, whereas long waves are reserved for short distances.

Discuss

Answer & Solution

Answer: Option A

Solution:

Short waves are more energetic than long waves. Short waves are unaffected by atmospheric disturbances. By convention, short waves are meant for long distances whereas long waves are reserved for short distances.

24

The frequency of ultrasound wave is typically

A) Above 20 kHz B) Above 20,000 kHz C) Below 20 kHz D) Below 02 kHz

Discuss

Answer & Solution

Answer: Option A

Solution:

Ultrasound refers to a sound wave with a frequency greater than the upper limit of human hearing, which is generally over 20 kHz. In general, humans can hear sounds with a frequency between 20 Hz and 20 kHz.

25

Which of the following has the highest frequency?

A) Cosmic rays B) X-rays C) Radio waves D) Microwaves

Discuss

Answer & Solution

Answer: Option A

Solution:

The frequency of Gamma rays is the highest. Gamma rays are the highest energy EM radiation and typically have energies greater than 100 keV, frequencies greater than 1019 Hz, and wavelengths less than 10 picometers.

26

Matter waves are

A) De Broglie waves B) Electromagnetic waves C) Transverse waves D) Longitudinal waves

Discuss

Answer & Solution

Answer: Option A

Solution:

Matter waves are De Broglie waves.

27

Two waves, each of amplitude 1.5 mm and frequency 10 Hz, are travelling in opposite direction with a speed of 20 mm/s. The distance in mm between adjacent nodes is :

A) 1.0 B) 1.2 C) 1.5 D) 2.0

Discuss

Answer & Solution

Answer: Option A

No explanation is given for this question. Let's Discuss on Board

28

Intensity of any wave is proportional to which of the following?

A) Amplitude B) Square of amplitude C) Square root of amplitude D) Cube of amplitude

Discuss

Answer & Solution

Answer: Option B

Solution:

Intensity of any wave is proportional to square of amplitude.

29

If density of oxygen is 16 times that of hydrogen, what will be their corresponding ratio of velocity of sound?

A) 4 : 1 B) 2 : 1 C) 1 : 16 D) 1 : 4

Discuss

Answer & Solution

Answer: Option D

Solution:

The corresponding ration of velocity of sound in oxygen and hydrogen is 1:4.

30

Which one of the following statements with regard to Jet stream, an upper level tropospheric wave, is not correct?

A) It is narrow band of high-velocity wind. B) It follows the wave path near the tropopause at elevations of 8 km to 15 km. C) Jet streams are typically continuous over long distances. D) In summer, the polar front jet achieves its maximum force.

Discuss

Answer & Solution

Answer: Option B

Solution:

It follows the wave path near the tropopause at elevations of 8 km to 15 km, this statement is not correct.