1 Marks Question

Question 1011 Mark

Can two astronauts talk on the surface of moon as they do on earth?

Answer

No, the astronauts cannot talk on the surface of moon as there is no atmosphere (air) on moon. Sound waves cannot travel without a medium.

View full question & answer→

Question 1021 Mark

For the harmonic travelling wave $\text{y}=2\cos2\pi(10\text{t}-0.0080\text{x}+3.5)$ where x and y are in cm and t is second. What is the phase difference between the oscillatory motion at two points separated by a distance of:

0.5m

Answer

$\text{y}=2\cos2\pi(10\text{t}-0.0080\text{x+3.5})$
$\text{y}=2\cos(20\pi\text{t}-0.0016\pi\text{x}+7.0\pi)$
Wave is propagated in $+\text{x}$ direction because $\omega\text{t}$ and kx are in with opposite sign standard equation $\text{y}=\text{a}\cos(\omega\text{t}-\text{kx}+\phi)$
a = 2, $\omega=20\pi,\ \text{k}=0.016\pi$ and $\phi=7\pi$
Path differencee p = 0.5m = 50cm
$\Delta\phi=\text{kp}=0.016\pi\times50=0.8\pi$ red.

View full question & answer→

Question 1031 Mark

What change is observed when a wave gets reflected from a hard, rigid support?

Answer

A phase change of $\pi$ radians.

View full question & answer→

Question 1041 Mark

What is the nature of ultrasonic waves and what is their frequency?

Answer

Ultrasonic waves are longitudinal waves in nature and have frequency greater than 20kHz.

View full question & answer→

Question 1051 Mark

Given below are some functions of x and t to represent the displacement of an elastic wave.
$\text{y}=4\sin(5\text{x}-\text{t/ 2})+3\cos(5\text{x}-\text{t/ 2})$

Answer

A stationary wave of the for $\text{y}=5\cos(4\text{x})\sin20\text{t}$ is a stationary wave so (b) (i).

View full question & answer→

Question 1061 Mark

What is the relation between velocity of the wave (v) frequency of the wave (v) and wavelength of the wave $(\lambda)$?

Answer

$\text{v}=\text{v}\lambda$

View full question & answer→

Question 1071 Mark

Why is sound heard in water more intense in comparison to sound heard in air?

Answer

This is because intensity of sound increases with increase in density of the medium.

View full question & answer→

Question 1081 Mark

Where does the pressure of larger magnitude exist at nodes or at antinodes?

Answer

Pressure is maximum at points of minimum displacement. So, it is maximum at nodes.

View full question & answer→

Question 1091 Mark

Name the factors affecting the velocity of sound in a medium.

Answer

Temperature, density and ratio $\gamma$ affect the velocity of sound in a medium.

View full question & answer→

Question 1101 Mark

Give one similarity and one difference between a S.H.M. and a Wave.

Answer

Similarity- Periodic nature.
Difference- Wave is a function of position and time, while a SHM is a function of time only.

View full question & answer→

Question 1111 Mark

What type of graph you expect between speed of sound through a gas and pressure of gas?

Answer

The graph will be straight line parallel to pressure axis.

View full question & answer→

Question 1121 Mark

Is it possible to have longitudinal waves on a string a transverse wave in a steel rod?

Answer

No, because string is not stretchable. It can neither be compressed nor rarefied. Yes, transverse waves are possible in steel rod, because steel has elasticity of shape.

View full question & answer→

Question 1131 Mark

What is the difference between a tone and a note?

Answer

Note is sound of particular frequency, while tone is of a particular intensity.

View full question & answer→

Question 1141 Mark

What propagates faster-a radio signal or sound in the air?

Answer

Radio wave.

View full question & answer→

Physics 1 Marks Question