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The kinetic energy of the photoelectrons increases by $0.52 eV$ when the wavelength of incident light is changed from $500 nm$ to another wavelength which is approximately

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Important Questions on Dual Nature of Radiation and Matter

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Physics>Modern Physics>Dual Nature of Radiation and Matter>Einstein's Equation of Photoelectric Effect

The magnetic field associated with a light wave is given, at the origin, by

B = B_{0} [\sin (3.14 \times 10^{7}) c t + \sin (6.28 \times 10^{7}) c t] .

If this light falls on a silver plate having a work function of

4 .7 eV,

what will be the maximum kinetic energy of the photoelectrons?

(c = 3 \times 10^{8} m s^{- 1}, h = 6 .6 \times 10^{- 34} J s)

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Physics>Modern Physics>Dual Nature of Radiation and Matter>Einstein's Equation of Photoelectric Effect

Light of wavelength

500 nm

is incident on a metal with work function

2.28 eV

. The de Broglie wavelength of the emitted electron is:

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Physics>Modern Physics>Dual Nature of Radiation and Matter>Einstein's Equation of Photoelectric Effect

A laser light of wavelength

660 nm

is used to weld Retina detachment. If a laser pulse of width

60 ms

and power

0.5 kW

is used, the approximate number of photons in the pulse are (Take Planck's Constant,

h = 6.62 \times 10^{- 34} J s)

HARD

Physics>Modern Physics>Dual Nature of Radiation and Matter>Einstein's Equation of Photoelectric Effect

A metal plate of area

1 \times 10^{- 4} m^{2}

is illuminated by a radiation of intensity

16 mW m^{- 2}

. The work function of the metal is

5 eV .

The energy of the incident photons is

10 eV

and only

10 %

of it produces photo electrons. The number of emitted photo electron per second and their maximum energy, respectively, will be:

[1 eV = 1.6 \times 10^{- 19} J]

HARD

Physics>Modern Physics>Dual Nature of Radiation and Matter>Einstein's Equation of Photoelectric Effect

In a historical experiment to determine Planck's constant, a metal surface was irradiated with light of different wavelengths. The emitted photoelectron energies were measured by applying a stopping potential. The relevant data for the wavelength

(λ)

of incident light and the corresponding stopping potential

(V_{0})

are given below:

$λ (μ m)$	$V_{0} (v o l t)$
0.3	2.0
0.4	1.0
0.5	0.4

Given that

c = 3 \times 10^{8} m s^{- 1} and e = 1.6 \times 10^{- 19} C,

Planck's constant (in units of

J s

) found from such an experiment is :

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Physics>Modern Physics>Dual Nature of Radiation and Matter>Einstein's Equation of Photoelectric Effect

Photons of energy

7 eV

are incident on two metals

A

and

B

with work functions

6 eV

and

3 eV

, respectively. The minimum de-Broglie wavelengths of the emitted photoelectrons with maximum energies are

λ_{A}

and

λ_{B}

, respectively, where

\frac{λ_{A}}{λ_{B}}

is nearly,

MEDIUM

Physics>Modern Physics>Dual Nature of Radiation and Matter>Einstein's Equation of Photoelectric Effect

The maximum velocity of the photoelectrons emitted from the surface is

v

when light of frequency

n

falls on a metal surface. If the incident frequency is increased to

3 n

, the maximum velocity of the ejected photoelectrons will be:

MEDIUM

Physics>Modern Physics>Dual Nature of Radiation and Matter>Einstein's Equation of Photoelectric Effect

A photoelectric material having work-function

ϕ_{0}

is illuminated with a light of wavelength

λ (λ < \frac{h c}{ϕ_{0}})

. The fastest photoelectron has a de Broglie wavelength

λ_{d}

. A change in wavelength of the incident light by

Δ λ

results in a change

Δ λ_{d}

λ_{d}

. The ratio

\frac{Δ λ_{d}}{Δ λ}

is proportional to

MEDIUM

Physics>Modern Physics>Dual Nature of Radiation and Matter>Einstein's Equation of Photoelectric Effect

Photons of wavelength

λ

are incident on a metal. The most energetic electrons ejected from the metal are bent into a circular are of radius R by a perpendicular magnetic field having a magnitude B. The work function of the metal is (Where symbols have their usual meanings).

MEDIUM

Physics>Modern Physics>Dual Nature of Radiation and Matter>Einstein's Equation of Photoelectric Effect

On a photosensitive material, when the frequency of incident radiation is increased by

30 %

, the kinetic energy of emitted photoelectrons increases from

0.4 eV

0.9 eV

. The work function of the surface is

MEDIUM

Physics>Modern Physics>Dual Nature of Radiation and Matter>Einstein's Equation of Photoelectric Effect

When ultraviolet radiation of a certain frequency falls on a potassium target, the photoelectrons released can be stopped completely by a retarding potential of

0.6 V .

If the frequency of the radiation is increased by

10 %,

this stopping potential rises to

0.9 V .

The work function of potassium is

HARD

Physics>Modern Physics>Dual Nature of Radiation and Matter>Einstein's Equation of Photoelectric Effect

The radiation corresponding to

3 \to 2

transition of hydrogen atom falls on a metal surface to produce photoelectrons. These electrons are made to enter a magnetic field of

3 \times 1 0^{- 4} T

. If the radius of the largest circular path followed by these electrons is 10.0 mm, the work function of the metal is close to :

HARD

Physics>Modern Physics>Dual Nature of Radiation and Matter>Einstein's Equation of Photoelectric Effect

For photo-electric effect with incident photon wavelength

λ

, the stopping potential is

V_{0}

. Identify the correct variation(s) of

V_{0}

with

λ

and

\frac{1}{λ}

MEDIUM

Physics>Modern Physics>Dual Nature of Radiation and Matter>Einstein's Equation of Photoelectric Effect

In a photocell circuit, the stopping potential, $V_{0}$ is a measure of the maximum kinetic energy of the photoelectrons. The following graph shows experimentally measured values of stopping potential versus frequency, $(ν)$ of incident light.

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The values of Planck's constant and the work function as determined from the graph are (taking the magnitude of electronic charge to be, $e = 1.6 \times 10^{- 19} C$ ),

MEDIUM

Physics>Modern Physics>Dual Nature of Radiation and Matter>Einstein's Equation of Photoelectric Effect

Radiation of wavelength

λ

is incident on a photocell. The fastest emitted photoelectron has a speed

v

. If the wavelength is changed to

\frac{3 λ}{4}

, the speed of the fastest emitted photoelectron will be

EASY

Physics>Modern Physics>Dual Nature of Radiation and Matter>Einstein's Equation of Photoelectric Effect

When the energy of the incident radiation is increased by

20 %,

the kinetic energy of the photoelectrons emitted from a metal surface increased from emitted

0.5 e V

0.8 e V .

The work function of the metal is:

HARD

Physics>Modern Physics>Dual Nature of Radiation and Matter>Einstein's Equation of Photoelectric Effect

A beam of electromagnetic radiation of intensity

6.4 \times 10^{- 5} W {cm}^{- 2}

is comprised of wavelength,

λ = 310 n m

. It falls normally on a metal (work function

ϕ = 2 eV

) of surface area of

1 {c m}^{2}

. If one in

10^{3}

photons ejects an electron, total number of electrons ejected in

1 s

10^{x}

(h c = 1240 e V n m, 1 e V = 1.6 \times 10^{- 19} J),

then

x

is ___________

EASY

Physics>Modern Physics>Dual Nature of Radiation and Matter>Einstein's Equation of Photoelectric Effect

The electric field of certain radiation is given by the equation

E = 200 \{\sin (4 π \times 10^{10}) t + \sin (4 π \times 10^{15}) t\}

falls in a metal surface having work function

2 .0 eV .

The maximum kinetic energy

(in eV)

of the photoelectrons is [Planck's constant

(h) = 6.63 \times 10^{- 34} J s

and electron charge

e = 1.6 \times 10^{- 19} C

]

MEDIUM

Physics>Modern Physics>Dual Nature of Radiation and Matter>Einstein's Equation of Photoelectric Effect

When a certain metallic surface is illuminated with monochromatic light of wavelength

λ,

the stopping potential for photoelectric current is

3 V_{0}

and when the same surface is illuminated with light of wavelength

2 λ,

the stopping potential is

V_{0} .

The threshold wavelength of this surface for photoelectric effect is

HARD

Physics>Modern Physics>Dual Nature of Radiation and Matter>Einstein's Equation of Photoelectric Effect

Light of wavelength $λ_{p h}$ falls on a cathode plate inside a vacuum tube as shown in the figure. The work function of the cathode surface is $ϕ$ and the anode is a wire mesh of conducting material kept at a distance $d$ from the cathode. A potential difference $V$ is maintained between the electrodes. If the minimum de Broglie wavelength of the electrons passing through the anode is $λ_{e},$ which of the following statement(s) is(are) true ?
Question Image

The kinetic energy of the photoelectrons increases by 0.52eV when the wavelength of incident light is changed from 500 nm to another wavelength which is approximately

Important Questions on Dual Nature of Radiation and Matter

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The kinetic energy of the photoelectrons increases by $0.52 eV$ when the wavelength of incident light is changed from $500 nm$ to another wavelength which is approximately