EASY

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When green light is incident on a certain metal surface, electrons are emitted but no electrons are emitted by yellow light. If red light is incident on the same metal surface

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Important Questions on Dual Nature of Matter and Radiation

EASY

Physics>Modern Physics>Dual Nature of Matter and Radiation>Electron Emission

A beam of photons with an energy of

10.5 eV

strike a metal plate. The photoelectrons are emitted with maximum velocity of

1.6 \times 10^{6} m s^{- 1}

. The work function of the metal is
(Assume mass of electron

= 9 \times 10^{- 31} kg

and Charge of electron

= 1.6 \times 10^{- 19} C

)

EASY

Physics>Modern Physics>Dual Nature of Matter and Radiation>Electron Emission

The surface of a metal is illuminated with a light of wavelength

400 nm

. The kinetic energy of the ejected photoelectrons was found to be

1.68 eV

. The work function of the metal is

(h c = 1240 eV nm)

EASY

Physics>Modern Physics>Dual Nature of Matter and Radiation>Electron Emission

The photoelectric threshold for a certain metal surface is $360 Å$ . If the metal surface is irradiated by a wavelength of $1100 Å$ , the kinetic energy of the emitted photoelectrons is

EASY

Physics>Modern Physics>Dual Nature of Matter and Radiation>Electron Emission

The maximum velocity of the photoelectron emitted by the metal surface is

v

. Charge and mass of the photoelectron is denoted by

e

and

m

respectively. The stopping potential in volt is

EASY

Physics>Modern Physics>Dual Nature of Matter and Radiation>Electron Emission

The photoelectric threshold wavelength of silver is

3250 \times 10^{- 10} m

. The velocity of the electron ejected from a silver surface by ultraviolet light of wavelength

2536 \times 10^{- 10} m

is:-

(G i v e n h = 4.14 \times 10^{- 15} eV s a n d c = 3 \times 10^{8} m s^{- 1})

EASY

Physics>Modern Physics>Dual Nature of Matter and Radiation>Electron Emission

In the experimental study of photoelectric effect, if

V_{0}

is the stopping potential and

v

is the frequency of the incident light on the metal the slope of graph plotted for

V_{0}

Versus

v

is (where

h, e

and

ϕ_{0}

are Planck's constant, charge of electron and work function of the metal respectively.

MEDIUM

Physics>Modern Physics>Dual Nature of Matter and Radiation>Electron Emission

The frequency and the intensity of incident beam of light falling on the surface of a photoelectric material is increased by a factor of two. This will

EASY

Physics>Modern Physics>Dual Nature of Matter and Radiation>Electron Emission

When a beam of

10.6 eV

photons of intensity

2.0 W m^{- 2}

falls on a metallic surface of area

1 \times 10^{- 4} m^{2}, 0.53 %

of the incident photons eject photoelectrons. What is the number of photoelectrons emitted per second?

EASY

Physics>Modern Physics>Dual Nature of Matter and Radiation>Electron Emission

In a photoelectric effect experiment, the threshold wavelength of light is

380 n m

. If the wavelength of incident light is

260 n m

, the maximum kinetic energy of emitted electrons will be
Given

E

(in

e V

)

= \frac{1237}{λ (i n n m)}

EASY

Physics>Modern Physics>Dual Nature of Matter and Radiation>Electron Emission

Light of certain frequency and intensity incident on a photosensitive material causes photoelectric effect. If both the frequency and intensity are doubled, the photoelectric saturation current becomes

EASY

Physics>Modern Physics>Dual Nature of Matter and Radiation>Electron Emission

If intensity of incident radiation in a photocell is increased, the stopping potential

EASY

Physics>Modern Physics>Dual Nature of Matter and Radiation>Electron Emission

A photoelectric surface is illuminated successively by monochromatic light of wavelength

λ

and

\frac{λ}{2}

. If the maximum kinetic energy of the emitted photoelectrons in the second case is 3 times that in the first case, the work function of the surface of the material is:
(

h

= Planck's constant,

c

= speed of light)

EASY

Physics>Modern Physics>Dual Nature of Matter and Radiation>Electron Emission

Threshold frequency for a metal is

15 \times 10^{14} Hz

. The light of wavelength

6000 Å

falls on the metal surface. Which one of the following statements is correct? [velocity of light,

c = 3 \times 10^{8} m s^{- 1}

]

EASY

Physics>Modern Physics>Dual Nature of Matter and Radiation>Electron Emission

The following graph represents the variation of photo current with anode potential for a metal surface. Here $I_{1}, I_{2}$ and $I_{3}$ represents intensities and $γ_{1}, γ_{2}, γ_{3}$ represents frequency for curves $1, 2$ and $3$ respectively, then