An electron (mass m ) with initial velocity v → = v 0 i ^ + v 0 j ^ is in an electric filed E → = - E 0 k ^ . If λ 0 is initial de-Broglie wavelength of electron, its de-Broglie wave length at time t is given by:

λ 0 1 + e 2 E 0 2 t 2 2 m 2 v 0 2

λ 0 2 1 + e 2 E 0 2 t 2 m 2 v 0 2

λ 0 1 + e 2 E 0 2 t 2 m 2 v 0 2

λ 0 2 + e 2 E 0 2 t 2 m 2 v 0 2

If the two metals A and B are exposed to radiation of wavelength 350 nm . The work functions of metals A and B are 4 . 8 eV and 2 . 2 eV . Then choose the correct option

Metal A will not emit photo-electrons

Metal B will not emit photo-electrons

Both metals A and B will emit photo-electrons

Both metals A and B will not emit photoelectrons

EASY

JEE Main

IMPORTANT

Earn 100

The surface of a metal is illuminated alternately with photons of energies $E_{1} = 4 eV$ and $E_{2} = 2.5 eV$ respectively. The ratio of maximum speeds of the photoelectrons emitted in the two cases is $2 .$ The work function of the metal in $(eV)$ is..........

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Important Questions on Dual Nature of Matter and Radiation

EASY

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 20 - Dual Nature of Matter and Radiation>JEE Main - 6 September 2020 Shift 2>Q 38

Assuming the nitrogen molecule is moving with

r . m . s

. velocity at

400 K

, the de-Broglie wave length of nitrogen molecule is close to : (Given : nitrogen molecule weight :

4 .64 \times 10^{- 26} kg

, Boltzman constant :

1 .38 \times 10^{- 23} J K^{- 1}

, Planck constant :

6 .63 \times 10^{- 34} J s

)

HARD

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 20 - Dual Nature of Matter and Radiation>JEE Main - 7th January 2020 Shift 1>Q 39

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

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 20 - Dual Nature of Matter and Radiation>JEE Main - 7th January 2020 Shift 2>Q 40

An electron (of mass

m

) and a photon have the same energy

E

in the range of a few

e V

. The ratio of the de-Broglie wavelength associated with the electron and the wavelength of the photon is (

c =

speed of light in vacuum)

HARD

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 20 - Dual Nature of Matter and Radiation>JEE Main - 8th January 2020 Shift 1>Q 41

When photon of energy

4.0 e V

strikes the surface of a metal

A,

the ejected photoelectrons have maximum kinetic energy

T_{A} e V

and de-Broglie wavelength

λ_{A} .

The maximum kinetic energy of photoelectrons liberated from another metal

B

by photon of energy

4.50 e V

T_{B} = (T_{A} - 1.5) e V .

If the de-Broglie wavelength of these photoelectrons

λ_{B} = 2 λ_{A},

then the work function of metal

B

is:

HARD

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 20 - Dual Nature of Matter and Radiation>JEE Main - 8th January 2020 Shift 2>Q 42

An electron (mass

m

) with initial velocity

\vec{v} = v_{0} \hat{i} + v_{0} \hat{j}

is in an electric filed

\vec{E} = - E_{0} \hat{k} .

λ_{0}

is initial de-Broglie wavelength of electron, its de-Broglie wave length at time

t

is given by:

HARD

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 20 - Dual Nature of Matter and Radiation>JEE Main - 9th January 2020 Shift 1>Q 43

Radiation, with wavelength

6561 Å

falls on a metal surface to produce photoelectrons. The electrons are made to enter a uniform magnetic field of

3 \times 10^{- 4} T

. If the radius of the largest circular path followed by the electrons is

10 m m

, the work function of the metal is close to:

EASY

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 20 - Dual Nature of Matter and Radiation>JEE Main - 9th January 2020 Shift 1>Q 44

A particle moving with kinetic energy

E

has de-Broglie wavelength

λ

. If energy

Δ E

is added to its energy, the wavelength becomes

\frac{λ}{2}

. Value of

Δ E,

is:

MEDIUM

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 20 - Dual Nature of Matter and Radiation>JEE Main - 9th January 2020 Shift 2>Q 45

An electron of mass

m

and magnitude of charge

e

at rest, gets accelerated by a constant electric field

E

. The rate of change of de-Broglie wavelength of this electron at a time

t

is (ignore relativistic effects)

The surface of a metal is illuminated alternately with photons of energies E1=4 eV and E2=2.5 eV respectively. The ratio of maximum speeds of the photoelectrons emitted in the two cases is 2. The work function of the metal in (eV) is..........

Important Questions on Dual Nature of Matter and Radiation

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The surface of a metal is illuminated alternately with photons of energies $E_{1} = 4 eV$ and $E_{2} = 2.5 eV$ respectively. The ratio of maximum speeds of the photoelectrons emitted in the two cases is $2 .$ The work function of the metal in $(eV)$ is..........