A point source of light is used in an experiment of photoelectric effects. If the distance between the source and the photoelectric surface is doubled, which of the following may result?

Photoelectric current will decrease.

Stopping potential will be halved.

Maximum kinetic energy of photoelectrons will decrease.

Stopping potential will increase slightly.

Electrons are emitted with kinetic energy T from a metal plate by an irradiation of light of intensity J and frequency v . Then, which of the following will be true?

Number of electrons emitted ∝ J

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If the energy of H-atom in the ground state is -2E, the velocity of photoelectron emitted when a photon having energy E_p strikes a stationary Li²⁺ ion in ground state is given by

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Important Questions on Dual Nature of Matter and Radiation

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Physics Crash Course JEE Advanced>Chapter 19 - Dual Nature of Matter and Radiation>Exercise 1>Q 3

In a photoelectric experiment under conditions of saturation current, we consider two different cross-section

A

and

B

as shown. Here,

v_{A}

and

v_{B}

represent the average speed of electrons at the two cross-sections.
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Physics Crash Course JEE Advanced>Chapter 19 - Dual Nature of Matter and Radiation>Exercise 1>Q 4

When a metal surface is illuminated by the light of wavelengths

400 nm

and

250 nm

, the maximum velocities of the photoelectrons ejected are

v

and

2 v

respectively. The work function of the metal is (

h =

Planck's constant,

c =

velocity of light in air):

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Physics Crash Course JEE Advanced>Chapter 19 - Dual Nature of Matter and Radiation>Exercise 1>Q 5

Monochromatic radiation emitted when electron on hydrogen atom jumps from first excited to the ground state irradiates a photosensitive material. The stopping potential is measured to be

3.57 V

. The threshold frequency of the material is

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Physics Crash Course JEE Advanced>Chapter 19 - Dual Nature of Matter and Radiation>Exercise 1>Q 6

When light of

2.5 eV

falls on a metal surface, the maximum kinetic energy of the electron is

T

. If incident radiation of

4 eV

falls on the same metal surface, the maximum kinetic energy of electrons is doubled. The work function of the metal is

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Physics Crash Course JEE Advanced>Chapter 19 - Dual Nature of Matter and Radiation>Exercise 1>Q 7

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

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Physics Crash Course JEE Advanced>Chapter 19 - Dual Nature of Matter and Radiation>Exercise 1>Q 8

Photons with energy

5 eV

are incident on a cathode

C

in a photoelectric cell. The maximum energy of emitted photoelectrons is

2 eV

. When photons of energy

6 eV

are incident on

C

no photoelectrons will reach the anode

A

, if the stopping potential of

A

relative to

C

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Physics Crash Course JEE Advanced>Chapter 19 - Dual Nature of Matter and Radiation>Exercise 1>Q 9

When photons of energy-

h v

fall on an aluminium plate (of work function is

E_{0}

), photoelectrons of maximum kinetic energy

K

are ejected. If the frequency of the radiation is doubled, the maximum kinetic energy of the ejected photoelectrons will be

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Physics Crash Course JEE Advanced>Chapter 19 - Dual Nature of Matter and Radiation>Exercise 1>Q 10

When the light of frequency $v_{1}$ is incident on metal with work function

W_{0}

(where

h v_{1} > W_{0}),

the photocurrent falls to zero at a stopping potential of

V_{1} .

If the frequency of light is increased to

v_{2}

, the stopping potential changes to

V_{2}

. Therefore, the charge of an electron is given by

If the energy of H-atom in the ground state is -2E, the velocity of photoelectron emitted when a photon having energy Ep strikes a stationary Li2+ ion in ground state is given by

Important Questions on Dual Nature of Matter and Radiation

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If the energy of H-atom in the ground state is -2E, the velocity of photoelectron emitted when a photon having energy E_p strikes a stationary Li²⁺ ion in ground state is given by