Photon Theory of Light

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JEE Advanced 1987

LEVELJEE Main

Four physical quantities are listed in Column I. Their values are listed in Column II in a random order

When the number of electrons striking the anode of an X-ray tube is increased the ........ of the emitted X-rays increases, while when the speeds of the electrons striking the anode are increased the cut-off wavelength of the emitted X-rays ........ .

LEVELJEE Main

The shortest wavelength of X-rays emitted from an X-ray tube depends on

(A)

the current in the tube

(B)

the voltage applied to the tube

(C)

the nature of the gas in tube

(D)

the atomic number of the target material

LEVELJEE Main

X-rays are produced in an X-ray tube operating at a given accelerating voltage. The wavelength of the continuous X-rays has values from

(A)

0

\infty

(B)

λ_{min}

\infty

where

λ_{min} > 0

(C)

0

λ_{max}

where

λ_{max} < \infty

(D)

λ_{min}

λ_{max}

where

0 < λ_{min} < λ_{max} < \infty

LEVELJEE Main

The potential difference applied to an X-ray tube is increased. As a result, in the emitted radiation

* Multiple Correct Options

(A)

the intensity increases

(B)

the minimum wavelength increases

(C)

the intensity remains unchanged

(D)

the minimum wavelength decreases

LEVELJEE Main

A potential difference of $20 kV$ is applied across an X-ray tube. The minimum wavelength of X-rays generated is ....... $\overset{˚}{A}$ .

JEE Advanced 2013

LEVELJEE Main

A pulse of light of duration $100 ns$ is absorbed completely by a small object initially at rest. Power of the pulse is $30 mW$ and the speed of light is $3 \times 1 0^{8} ms^{- 1}$ . The final momentum of the object is

(A)

0.3 \times 1 0^{- 17} kg-ms^{- 1}

(B)

1.0 \times 1 0^{- 17} kg-ms^{- 1}

(C)

3.0 \times 1 0^{- 17} kg-ms^{- 1}

(D)

9.0 \times 1 0^{- 17} kg-ms^{- 1}

JEE Advanced 2020

LEVELJEE Main

In an X-ray tube, electrons emitted from a filament (cathode) carrying current $I$ hit a target (anode) at a distance $d$ from the cathode. The target is kept at a potential $V$ higher than the cathode resulting in emission of continuous and characteristic X-rays. If the filament current $I$ is decreased to $\frac{I}{2}$ , the potential difference $V$ is increased to $2 V$ , and the separation distance $d$ is reduced to $\frac{d}{2}$ , then

* Multiple Correct Options

(A)

the cut-off wavelength will reduce to half, and the wavelengths of the characteristic X-rays will remain the same

(B)

the cut-off wavelength as well as the wavelengths of the characteristic X-rays will remain the same

(C)

the cut-off wavelength will reduce to half, and the intensities of all the X-rays will decrease

(D)

the cut-off wavelength will become two times larger, and the intensity of all the X-rays will decrease

JEE Advanced 2019

LEVELJEE Advanced

A perfectly reflecting mirror of mass $M$ mounted on a spring constitutes a spring-mass system of angular frequency $Ω$ such that $\frac{4 π M Ω}{h} = 1 0^{24} m^{- 2}$ with $h$ as Planck's constant. $N$ photons of wavelength $λ = 8 π \times 1 0^{- 6} m$ strike the mirror simultaneously at normal incidence such that the mirror gets displaced by $1 μ m$ . If the value of $N$ is $x \times 1 0^{12}$ , then the value of $x$ is_______. [Consider the spring as massless]

LEVELJEE Main

If a source of power $4 kW$ produces $1 0^{20}$ photons/second, the radiation belong to a part of the spectrum called

γ

-rays

JEE Main 2021

LEVELJEE Main

An X-ray tube is operated at $1.24$ million volt. The shortest wavelength of the produced photon will be

(A)

1 0^{- 3} nm

(B)

1 0^{- 1} nm

(C)

1 0^{- 2} nm

(D)

1 0^{- 4} nm

JEE Main 2020

LEVELJEE Main

Two sources of light emit X-rays of wavelength 1 nm and visible light of wavelength 500 nm, respectively. Both the sources emit light of the same power 200 W. The ratio of the number density of photons of X-rays to the number density of photons of the visible light of the given wavelengths is

(A)

\frac{1}{250}

\frac{1}{500}

JEE Main 2021

LEVELJEE Main

The wavelength of an X-ray beam is $10 \overset{˚}{A}$ . The mass of a fictitious particle having the same energy as that of the X-ray photons is $\frac{x}{3} h kg$ . The value of $x$ is ............ . ( $h = Planck’s constant$ )

JEE Main 2017

LEVELJEE Main

An electron beam is accelerated by a potential difference $V$ to hit a metallic target to produce X-rays. It produces continuous as well as characteristic X-rays. If $λ_{min}$ is the smallest possible wavelength of X-rays in the spectrum, the variation of $lo g λ_{min}$ with $lo g V$ is correctly represented in

A $2 mW$ laser operates at a wavelength of $500 nm$ . The number of photons that will be emitted per second is [Given, Planck's constant $h = 6.6 \times 1 0^{- 34} Js$ , speed of light $c = 3.0 \times 1 0^{8} m/s$ ]

(A)

1 \times 1 0^{16}

(B)

5 \times 1 0^{15}

(C)

1.5 \times 1 0^{16}

(D)

2 \times 1 0^{16}

LEVELBoard

Photon of frequency $ν$ has a momentum associated with it. If $c$ is the velocity of light, the momentum is

(A)

\frac{ν}{c}

(B)

h ν c

(C)

\frac{h ν}{c ^{2}}

(D)

\frac{h ν}{c}

JEE Main 2021

LEVELJEE Main

If $2.5 \times 1 0^{- 6}$ N average force is exerted by a light wave on a non-reflecting surface of $30 cm^{2}$ area during 40 min of time span, the energy flux of light just before it falls on the surface is ...... $W/cm^{2}$ . (Round off to the nearest integer. Assume complete absorption and normal incidence conditions are there.)

Four physical quantities are listed in Column I. Their values are listed in Column II in a random order

List-I

List-II

The X-ray beam coming from an X-ray tube will be

When the number of electrons striking the anode of an X-ray tube is increased the ........ of the emitted X-rays increases, while when the speeds of the electrons striking the anode are increased the cut-off wavelength of the emitted X-rays ........ .

The shortest wavelength of X-rays emitted from an X-ray tube depends on

X-rays are produced in an X-ray tube operating at a given accelerating voltage. The wavelength of the continuous X-rays has values from

The potential difference applied to an X-ray tube is increased. As a result, in the emitted radiation

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } A potential difference of 20 kV is applied across an X-ray tube. The minimum wavelength of X-rays generated is ....... A˚.

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } If a source of power 4 kW produces 1020 photons/second, the radiation belong to a part of the spectrum called

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } An X-ray tube is operated at 1.24 million volt. The shortest wavelength of the produced photon will be

Two sources of light emit X-rays of wavelength 1 nm and visible light of wavelength 500 nm, respectively. Both the sources emit light of the same power 200 W. The ratio of the number density of photons of X-rays to the number density of photons of the visible light of the given wavelengths is

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } Photon of frequency ν has a momentum associated with it. If c is the velocity of light, the momentum is

A potential difference of $20 kV$ is applied across an X-ray tube. The minimum wavelength of X-rays generated is ....... $\overset{˚}{A}$ .

If a source of power $4 kW$ produces $1 0^{20}$ photons/second, the radiation belong to a part of the spectrum called

An X-ray tube is operated at $1.24$ million volt. The shortest wavelength of the produced photon will be

Photon of frequency $ν$ has a momentum associated with it. If $c$ is the velocity of light, the momentum is