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If the work function of potassium is $2 eV$ , then its photoelectric threshold wavelength is

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Important Questions on Modern Physics

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JEE Advanced

IMPORTANT

Complete Study Pack for Engineering Entrances Objective Physics Vol 2>Chapter 9 - Modern Physics>Objective Problems [Level 1]>Q 113

Threshold wavelength for a metal is

5200 Å

. The photoelectron will be ejected, if it is irradiated by light from

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Complete Study Pack for Engineering Entrances Objective Physics Vol 2>Chapter 9 - Modern Physics>Objective Problems [Level 1]>Q 114

A photocell is illuminated by a point source of light, which is placed at a distance

d

from the cell. If the distance becomes

\frac{d}{2}

, then number of electrons emitted per second will

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Complete Study Pack for Engineering Entrances Objective Physics Vol 2>Chapter 9 - Modern Physics>Objective Problems [Level 1]>Q 115

Light of frequency

4 ν_{0}

is incident on the metal of threshold frequency

ν_{0}

. The maximum kinetic energy of the emitted photoelectron is

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Complete Study Pack for Engineering Entrances Objective Physics Vol 2>Chapter 9 - Modern Physics>Objective Problems [Level 1]>Q 116

In a photoelectric experiment, the stopping potential

V_{S}

is plotted against the frequency

v

of incident light. The resulting curve is a straight line which makes an angle

θ

with the

v

-axis. The

tanθ

will be equal to (

ϕ =

work function of surface)

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Complete Study Pack for Engineering Entrances Objective Physics Vol 2>Chapter 9 - Modern Physics>Objective Problems [Level 1]>Q 117

The work functions of metals

A

and

B

are in the ratio

1 : 2

. If light of frequencies

f

and

2 f

are incident on metal surfaces of

A

and

B

respectively, the ratio of the maximum kinetic energies of photoelectron emitted is (

f

is greater than threshold frequency of

A, 2 f

is greater than threshold frequency of

B

)

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Complete Study Pack for Engineering Entrances Objective Physics Vol 2>Chapter 9 - Modern Physics>Objective Problems [Level 1]>Q 118

The surface of some material is radiated, by waves of

λ_{1} = 3.5 \times 10^{- 7} m

and

λ_{2} = 5.4 \times 10^{- 7} m

respectively. The ratio of the stopping potential in two cases is

2 : 1

. The work function of the material is

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Complete Study Pack for Engineering Entrances Objective Physics Vol 2>Chapter 9 - Modern Physics>Objective Problems [Level 1]>Q 119

The retarding potential necessary to stop the emission of photoelectron, when a target material of work function

1.24 eV

is irradiated with light of wavelength

4.36 \times 10^{- 7} m

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JEE Advanced

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Complete Study Pack for Engineering Entrances Objective Physics Vol 2>Chapter 9 - Modern Physics>Objective Problems [Level 1]>Q 120

Light of wavelength

3500 Å

is incident on two metals

A

and

B, A

of work function

4.2 eV

and

B

of work function

1.19 eV

. The photoelectron will be emitted by

If the work function of potassium is 2 eV, then its photoelectric threshold wavelength is

Important Questions on Modern Physics

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If the work function of potassium is $2 eV$ , then its photoelectric threshold wavelength is