Threshold frequency for a metal is 10 15 Hz. Light of λ = 4000 A 0 falls on its surface. Which of the following statements is correct

No photoelectric emission takes place

Photo-electrons come out with zero speed

Photo-electrons come out with 10 3 m/sec speed

Photo-electrons come out with 10 5 m/sec speed

Physics - Dual Nature Radiation Matter - Quiz-3

The kinetic energy of an electron with de-Broglie wavelength of 0.3 nanometer is

0%
0.168 eV
0%

16.8 eV
0%

1.68 eV
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2.5 eV

The wavelength of de-Broglie wave is 2 $μ$ m, then its momentum is (h = $6.63 \times 10^{- 34}$ J-s)

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() $3.315 \times 10^{- 28}$ kg-m/s
0%
() $1.66 \times 10^{- 28}$ kg-m/s
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() $4.97 \times 10^{- 28}$ kg-m/s
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() $9.9 \times 10^{- 28}$ kg-m/s

If the kinetic energy of a free electron doubles, its de-Broglie wavelength changes by the factor

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$\frac{1}{\sqrt{2}}$
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$\sqrt{2}$
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$\frac{1}{2}$
0%

2

The energy that should be added to an electron to reduce its de Broglie wavelength from one nm to 0.5 nm is

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Four times the initial energy
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Equal to the initial energy
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Twice the initial energy
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Thrice the initial energy

The wavelength of the matter wave is independent of

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Mass
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Velocity
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Momentum
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Charge

The energy of a photon of wavelength $λ$ is given by

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h $λ$
0%

ch $λ$
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$λ$ /hc
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hc/ $λ$

The rest mass of the photon is

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0
0%

$\infty$
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Between 0 and $\infty$
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Equal to that of an electron

The momentum of a photon of energy hv will be

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hv
0%

hv/c
0%

hvc
0%

h/v

If the momentum of a photon is p, then its frequency is

where m is the rest mass of the photon

0%

$\frac{ph}{c}$
0%

$\frac{pc}{h}$
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$\frac{mh}{c}$
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$\frac{mc}{h}$

An AIR station is broadcasting the waves of wavelength 300 metres. If the radiating power of the transmitter is 10 kW, then the number of photons radiated per second is

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(1) $1.5 \times 10^{29}$
0%

(2) $1.5 \times 10^{31}$
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(3) $1.5 \times 10^{33}$
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(4) $1.5 \times 10^{35}$

The energy of a photon is E = hv and the momentum of photon $p = \frac{h}{λ}$ , then the velocity of photon will be

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Ep
0%
E/p
0%

${(\frac{E}{P})}^{2}$
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$3 \times 10^{8} m / s$

The approximate wavelength of a photon of energy 2.48 eV is

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500 Å
0%

5000 Å
0%

2000 Å
0%

1000 Å

The energy of a quanta of frequency $10^{15}$ Hz and $h = 6.6 \times 10^{- 34} J - \sec$ will be

0%

$6.6 \times 10^{- 19} J$
0%

$6.6 \times 10^{- 12} J$
0%

$6.6 \times 10^{- 49} J$
0%

$6.6 \times 10^{- 41} J$

Wavelength of a 1 keV photon is $1.24 \times 10^{- 9} m$ . What is the frequency of 1 MeV photon?

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(a) $1.24 \times 10^{15} Hz$
0%
(b) $2.4 \times 10^{20} Hz$
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(c) $1.24 \times 10^{18} Hz$
0%
(d) $2.4 \times 10^{23} Hz$

What is the momentum of a photon having frequency $1.5 \times 10^{13} Hz$ ?

0%
() $3.3 \times 10^{- 29} kg m / s$
0%
() $3.3 \times 10^{- 34} kg m / s$
0%
() $6.6 \times 10^{- 34} kg m / s$
0%
() $6.6 \times 10^{- 30} kg m / s$

The energy of a photon of light of wavelength 450 nm is

0%
$4.4 \times 10^{- 19} J$
0%

$2.5 \times 10^{- 19} J$
0%

$1.25 \times 10^{- 17} J$
0%

$2.5 \times 10^{- 17} J$

Which of the following is true for photon

0%
$E = \frac{hc}{λ}$
0%

$E = \frac{1}{2} {mu}^{2}$
0%

$p = \frac{E}{2 v}$
0%

$E = \frac{1}{2} {mc}^{2}$

Einstein's photoelectric equation states that $E_{k} = hv - ϕ$ . In this equation $E_{k}$ refers to

0%

Maximum kinetic energy of the emitted electrons
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Kinetic energy of all the emitted electrons
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Mean kinetic energy of the emitted electrons
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Minimum kinetic energy of the emitted electrons

Kinetic energy with which the electrons are emitted from the metal surface due to photoelectric effect is

0%

Independent of the intensity of illumination
0%

Independent of the frequency of light
0%

Inversely proportional to the intensity of illumination
0%

Directly proportional to the intensity of illumination

The threshold wavelength for photoelectric emission from a material is 5200 Å. Photo-electrons will be emitted when this material is illuminated with monochromatic radiation from :

0%

50-watt infrared lamp
0%

50-watt ultraviolet lamp
0%

1-watt ultraviolet lamp
0%

Both (2) and (3)

Threshold frequency for a metal is $10^{15}$ Hz. Light of $λ = 4000$ $\overset{0}{A}$ falls on its surface. Which of the following statements is correct

0%

No photoelectric emission takes place
0%

Photo-electrons come out with zero speed
0%

Photo-electrons come out with $10^{3}$ m/sec speed
0%

Photo-electrons come out with $10^{5}$ m/sec speed

Einstein got Nobel prize on which of the following works

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Mass-energy relation
0%

Special theory of relativity
0%

Photoelectric equation
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(a) and (b) both

The photo-electrons emitted from a surface of sodium metal are such that

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They all are of the same frequency
0%

They have the same kinetic energy
0%

They have the same de Broglie wavelength
0%

They have their speeds varying from zero to a certain maximum

A metal surface of work function 1.07 eV is irradiated with light of wavelength 332 nm. The retarding potential required to stop the escape of photo-electrons is

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() 4.81 eV
0%
() 3.74 eV
0%
() 2.66 eV
0%
() 1.07 eV

In a photo cell, the photo-electrons emission takes place

0%
After $10^{- 1}$ sec on incident of light rays
0%

After $10^{- 3}$ sec on incident of light rays
0%

After $10^{- 6}$ sec on incident of light rays
0%

After $10^{- 8}$ sec on incident of light rays

When light falls on a metal surface, the maximum kinetic energy of the emitted photo-electrons depends upon

0%
The time for which light falls on the metal
0%

Frequency of the incident light
0%

Intensity of the incident light
0%

Velocity of the incident light

The electrons are emitted in the photoelectric effect from a metal surface

0%

Only if the frequency of the incident radiation is above a certain threshold value
0%

Only if the temperature of the surface is high
0%

At a rate that is independent of the nature of the metal
0%

With a maximum velocity proportional to the frequency of the incident radiation

The work function of a metal is 4.2 eV, its threshold wavelength will be:

0%
4000 Å
0%

3500 Å
0%

2955 Å
0%

2500 Å

The number of photo-electrons emitted per second from a metal surface increases when:

0%
the energy of incident photons increases.
0%
the frequency of incident light increases.
0%
the wavelength of the incident light increases.
0%
the intensity of the incident light increases.

The work function of metal is 1 eV. Light of wavelength 3000 Å is incident on this metal surface. The velocity of emitted photo-electrons will be

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() 10 m/sec
0%
() $1 \times 10^{3}$ m/sec
0%
() $1 \times 10^{4}$ m/sec
0%
() $1 \times 10^{6}$ m/sec

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Practice Physics Quiz Questions and Answers

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Practice Physics Quiz Questions and Answers

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