Physics Test - 33

Ultraviolet has the shortest wavelength among the given options.

Gamma rays have the shortest wavelength and highest energy in the electromagnetic spectrum.

Radio waves have the highest wavelength and least energy. Radio waves consist of Radar, Amplitude Modulated (AM), Frequency Modulation, and TV.

Electromagnetic spectrum (in order of increasing wavelength) gamma rays, x-rays, ultraviolet, visible light (VIBGYOR), infrared, microwaves, radio waves

Given:

Force \(F=20+10 y\)

Particles moves from y = 0 to y = 1m

So, work done on a particle is given as:

\(W=\int_{0}^{1} F \cdot d y=\int_{0}^{1} 20+10 {y}\)

\(\therefore W=\left[20 y+\frac{10 y^{2}}{2}\right]_{0}^{1}\)

\(=20+5=25 J\)

The property of the sound waves that determines the pitch of the sound is its frequency.

The higher the frequency of a sound, the higher pitch. Amplitude is the maximum displacement of vibrating particles of the medium from their mean position. When sound travels from one medium to another, both its velocity and wavelength undergo changes.

Electric field intensity is zero inside the hollow spherical charged conductor. So no work is done in moving a test charge inside the conductor and on its surface. Therefore there is no potential difference between any two points inside or on the surface of the conductor.

An n-type semiconductor is obtained by doping a semiconductor with a pentavalent impurity. The impurity so added produces free electrons. Therefore, in an n-type semiconductor, the electrons are majority carriers and holes are minority carriers and pentavalent atoms are the dopants.

The viscosity of liquids decreases with an increase in temperature while it increases in the case of gases.

Viscosity is a measure of resistance to flow which arises due to the internal friction between layers of fluid. This resistance to fluid motion is like internal friction analogous to friction when a solid moves on a surface.

Strong intermolecular forces between molecules hold them together and resist the movement of layers past one another.

When a liquid is heated, the kinetic energy of its molecules increases and the intermolecular attraction becomes weaker. Hence, the viscosity of a liquid decreases with increase in its temperature.

When a suitable trivalent impurity (also called acceptor impurities as these accept electrons from the covalent bond of intrinsic semiconductor) is added to pure semiconductor crystal, we get an extrinsic semiconductor known as a p-type semiconductor.

Angular momentum,

\(L=l \times \omega\)----(1)

Rotational kinetic energy,

\(E=\frac{1}{2} I \omega^{2}\)

\(\Rightarrow \omega=\sqrt{\frac{2 E}{I}}\)---(2)

Substituting (2) in (1) we get

\(L=I \times \sqrt{\frac{2 E}{I}}\)

\(=\sqrt{2 E I}\)

Therefore, \({L} \propto \sqrt{{E}}\)

'The amplitude of the resultant wave is equal to the sum of the amplitudes of individual waves' is correct for the constructive interference of the two harmonic waves.

When two or more waves come together at some point in space then the resultant disturbance wave is the vector sum of disturbance of the individual waves.

When two waves superimpose then the resultant amplitude of the wave at that point is the vector sum of amplitudes of each individual wave. This phenomenon is called the interference of waves.

If two waves superimpose with each other in the same phase, the amplitude of the resultant is equal to the sum of the amplitudes of individual waves resulting in the maximum intensity of light, this is known as constructive interference.

Given:

\(n_{1}=4\) and \(n_{2}=5\)

The wavelength of the radiations emitted from the hydrogen atom is given by:

\(\frac{1}{\lambda_{1}}=R\left[\frac{1}{(4)^{2}}-\frac{1}{(5)^{2}}\right]\)

\(= R\left[\frac{1}{16}-\frac{1}{25}\right]=\frac{9 R}{400}\).....(1)

When electrons jump from \(4^{\text {th }}\) to \(1^{\text {st }}\) orbit, then the wavelength of the radiations emitted from the hydrogen atom is given by:

\(\frac{1}{\lambda_{2}}=R\left[\frac{1}{(1)^{2}}-\frac{1}{(4)^{2}}\right]\)

\(= R\left[\frac{1}{1}-\frac{1}{16}\right]=\frac{15 R}{16}\).....(2)

Divide equation (1) and (2), we get,

\(\frac{\lambda_{1}}{\lambda_{2}}=\frac{400 \times 15 R}{9 R \times 16}\)

\(=\frac{125}{3}\)

\(=125 : 3\)