Tag: physics

Questions Related to physics

The velocity of sound in air is not affected by change in 

physics world of sounds characteristics of sound wave time period, frequency and amplitude of sound sound waves are longitudinal waves

  1. the moisture content of the air.

  2. the temperature of air.

  3. the atmospheric pressure.

  4. the composition of air.

Show answer
Correct Option: C
Explanation:

The speed of sound depends on temperature. The formula relating speed of sound and temperature is as follows:

$v = 331 + 0.6 \times T$, where $T$ is temperature in absolute scale and $v$ is in $m/s$.
Humidity has little effect on the speed of sound.
Air pressure has no effect at all in an ideal gas approximation. This is because pressure and density both contribute to sound velocity equally, and in an ideal gas the two effects cancel out each other, leaving only the effect of temperature.
Composition of air has also almost no effect on the speed of sound.

Consider the following
l. Waves created on the surfaces of a water pond by a vibrating source.
ll. Wave created by an oscillating electric field in air.
lll. Sound waves travelling under water. 
Which of these can be polarized

physics world of sounds characteristics of sound wave time period, frequency and amplitude of sound sound waves are longitudinal waves

  1. l and ll

  2. ll only

  3. ll and lll

  4. l, ll, and lll

Show answer
Correct Option: A
Explanation:

Sound waves are longitude and can not be polarized. Answer A

Choose the Correct answer from alternative given.
The phenomena which is not explained by Huygen's construction of wavefront.

physics wave optics huygens wave theory and wavefront wave propagation (huygens' construction) theories on light wave behaviour

  1. reflection

  2. diffraction

  3. refraction

  4. origin of spectra

Show answer
Correct Option: D
Explanation:

The Huygen's construction of wavefront does not explain the phenomena of spectra.

Choose the Correct answer from alternative given.
Wavefront is the locus of all points, where the particles of the medium vibrate with the same

physics wave optics huygens wave theory and wavefront wave propagation (huygens' construction) theories on light wave behaviour

  1. phase

  2. amplitude

  3. frequency

  4. period

Show answer
Correct Option: A
Explanation:

Wavefront is the locus of all points, where the particles of the medium vibrate with the same phase.

Choose the Correct answer from alternative given.
The idea of secondary wavelets for the propagation of a wave was first given by:

physics wave optics huygens wave theory and wavefront wave propagation (huygens' construction) theories on light wave behaviour

  1. Newton

  2. Huygens

  3. Maxwell

  4. Fresnel

Show answer
Correct Option: B
Explanation:

According to the Huygens theory, all the points on a  wavefront act as source for a secondary wavefront or a wavelet which spread outward from the point and move at the speed of light.

The phenomena which is not explained by Huygen's construction of the wavefront

physics wave optics huygens wave theory and wavefront wave propagation (huygens' construction) theories on light wave behaviour

  1. reflection

  2. diffraction

  3. refraction

  4. origin of spectra

Show answer
Correct Option: D
Explanation:

The Huygen's construction of wavefront does not explain the phenomena of origin of spectra.

Wavefront is the locus of all points, where the particles of the medium vibrate with the same.

physics wave optics huygens wave theory and wavefront wave propagation (huygens' construction) theories on light wave behaviour

  1. phase

  2. amplitude

  3. frequency

  4. period

Show answer
Correct Option: A
Explanation:

Wavefront is the locus of all points, where the particles of the medium vibrate with the same phase

The wavelength of characteristic $X \text { -ray } K _ { \alpha }$ a line emitted by hydrogen like atom is $0.32 \mathrm { A } ^{ \circ }$. The wavelength of $K _ { \beta }$ line emitted by the same element is 

physics wave optics huygens wave theory and wavefront wave propagation (huygens' construction) theories on light wave behaviour

  1. $0.21 { \mathrm { A } }$

  2. $0.27 \mathrm { A }$

  3. $0.33 \mathrm { A }$

  4. $0.40 \hat { \mathrm { A } }$

Show answer
Correct Option: A

A transverse wave travelling in a denser medium is reflected from a rarer medium. Then, 

physics wave optics huygens wave theory and wavefront wave propagation (huygens' construction) theories on light wave behaviour

  1. an incident crest is reflected as a crest

  2. an incident crest is reflected as a trough

  3. there is a phase change of $2\pi$ rad

  4. there is a phase change of $\pi/2$ rad

Show answer
Correct Option: A

The radius of a wavefront as the waves propagate

physics wave optics huygens wave theory and wavefront wave propagation (huygens' construction) theories on light wave behaviour

  1. decreases

  2. increases

  3. becomes zero

  4. sometimes decreases and sometimes increases.

Show answer
Correct Option: B
Explanation:

As the waves propagates, it goes on creating secondary sources of light, resulting in increase in its radius.