NEET-UG SERIES

Physics

Dual Nature Of Matter

33 previous year questions.

Volume: 33 Ques

Yield: High

High-Yield Trend

2

2020

1

2019

2

2018

1

2017

3

2016

2

2015

1

2014

2

2013

3

2012

2

2011

2

2010

1

2008

2

2007

1

2006

2

2001

Chapter Questions
33 MCQs

01

PYQ 1990

medium

physics ID: neet-ug-

A radio transmitter operates at a frequency 880 kHz and a power of 10 kW. The number of photons emitted per second is

1

2

3

4

02

PYQ 1991

medium

physics ID: neet-ug-

An electron with (rest mass) moves with a speed of 0.8 c. Its mass when it moves with this speed is

1

2

3

4

03

PYQ 1993

medium

physics ID: neet-ug-

When light of wavelength 300 nm (nanometer) falls on a photoelectric emitter, photoelectrons are liberated. For another emitter, however, light of 600 nm wavelength is sufficient for creating photoemission. What is the ratio of the work functions of the two emitters ?

1

1:02

2

2:01

3

4:01

4

1:04

04

PYQ 1996

medium

physics ID: neet-ug-

An electron of mass m and charge e is accelerated from rest through a potential difference V in vacuum. Its final velocity will be

1

2

3

4

05

PYQ 1997

medium

physics ID: neet-ug-

Which of the following statement is correct?

1

The photocurrent increases with intensity of light

2

The stopping potential increases with increase of incident light

3

The current in photocell increases with increasing frequency

4

The photocurrent is proportional to the applied voltage.

06

PYQ 2000

easy

physics ID: neet-ug-

By photoelectric effect, Einstein proved

1

2

3

4

07

PYQ 2001

medium

physics ID: neet-ug-

In Thomson mass spectrograph then the velocity of electron beam will be

1

2

3

4

08

PYQ 2001

medium

physics ID: neet-ug-

Which one among the following shows particle nature of light?

1

photo electric effect

2

interference

3

refraction

4

polarization.

09

PYQ 2006

medium

physics ID: neet-ug-

A photocell employs photoelectric effect to convert :-

1

change in the frequency of light into a change in the electric current

2

change in the frequency of light into a change in electric voltage

3

change in the intensity of illumination into a change in photoelectric current

4

change in the intensity of illumination into a change in the work function of the photocathode.

10

PYQ 2007

medium

physics ID: neet-ug-

A watt source emits monochromatic light of wavelength . When placed away, it liberates photoelectrons from a photosensitive metallic surface. When the source is moved to a distance of, the number of photo electrons liberated will:

1

be reduced by a factor of 8

2

be reduced by a factor of 16

3

be reduced by a factor of 2

4

be reduced by a factor of 4

11

PYQ 2007

medium

physics ID: neet-ug-

A beam of electron passes undeflected through mutually perpendicular electric and magnetic fields. If the electric field is switched off, and the same magnetic field is maintained, the electrons move

1

in a circular orbit

2

along a parabolic path

3

along a straight line

4

in an elliptical orbit.

12

PYQ 2008

medium

physics ID: neet-ug-

A particle of mass 1 mg has the same wavelength as an electron moving with a velocity of The velocity of the particle is (mass of electron=

1

2

3

4

13

PYQ 2010

medium

physics ID: neet-ug-

When monochromatic radiation of intensity falls on a metal surface, the number of photoeleetrons and their maximum kinetic energy are and respectively. If the intensity of radiation is, the number of emitted electrons and their maximum kinetic energy are respectively

1

N and 2 T

2

2N and T

3

2 N and 2T

4

N and T

14

PYQ 2010

medium

physics ID: neet-ug-

A beam of cathode rays is subjected to crossed electric and magnetic fields . The fields are adjusted such that the beam is not deflected. The specific charge of the cathode rays is given by (Where is the potential difference between cathode and anode)

1

2

3

4

15

PYQ 2011

medium

physics ID: neet-ug-

In photoelectric emission process from a metal of work function, the kinetic energy of most energetic electrons is . The corresponding stopping potential is

1

1.8V

2

1.3V

3

0.5 V

4

2.3 V

16

PYQ 2011

medium

physics ID: neet-ug-

Electrons used in an electron microscope are accelerated by a voltage of . If the voltage is increased to then the de-Broglie wavelength associated with the electrons would

1

increase by 2 times

2

decrease by 2 times

3

decrease by 4 times

4

increase by 4 times

17

PYQ 2012

medium

physics ID: neet-ug-

An particle moves in a circular path of radius in the presence of a magnetic field of The de Broglie wavelength associated with the particle will be (Take,)

1

2

3

4

18

PYQ 2012

medium

physics ID: neet-ug-

If the momentum of an electron is changed by P, then the de Broglie wavelength associated with it changes by The initial momentum of electron will be

1

200P

2

400P

3

4

100P

19

PYQ 2012

medium

physics ID: neet-ug-

A sodium street lamp emits yellow light of wavelength Assuming it to be efficient in converting electrical energy to light, the number of photons of yellow light it emits per second is

1

2

3

4

20

PYQ 2013

medium

physics ID: neet-ug-

For photoelectric emission from certain metal the cutoff frequency is v. If radiation of frequency 2v impinges on the metal plate, the maximum possible velocity of the emitted electron will be (m is the electron mass) :

1

2

3

4

21

PYQ 2013

medium

physics ID: neet-ug-

The wavelength of an electron and of a photon of same energy E are related by:

1

2

3

4

22

PYQ 2014

medium

physics ID: neet-ug-

When the energy of the incident radiation is increased by the kinetic energy of the photoelectrons emitted from a metal surface increased from 0.5 eV to 0.8 eV. The work function of the metal is

1

0.65 eV

2

1.0 eV

3

1.3 eV

4

1.5 eV

23

PYQ 2015

medium

physics ID: neet-ug-

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

1

2

3

4

24

PYQ 2015

medium

physics ID: neet-ug-

A photoelectric surface is illuminated successively by monochromatic light of wavelength and 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)

1

2

3

4

25

PYQ 2016

medium

physics ID: neet-ug-

When a metallic surface is illuminated with radiation of wavelength, the stopping potential is V. If the same surface is illuminated with radiation of wavelength, the stopping potential is . The threshold wavelength for the metallic surface is :

1

2

3

4

26

PYQ 2016

medium

physics ID: neet-ug-

Electrons of mass with de-Broglie wavelength fall on the target in an X-ray tube. The cutoff wavelength of the emitted X-ray is

1

2

3

4

27

PYQ 2016

medium

physics ID: neet-ug-

An electron of mass m and a photon have same energy E. The ratio of de-Broglie wavelengths associated with them is :

1

2

3

c

4

c

28

PYQ 2017

medium

physics ID: neet-ug-

The de-Broglie wavelength of a neutron in thermal equilibrium with heavy water at a temperature (Kelvin) and mass, is :

1

2

3

4

29

PYQ 2018

medium

physics ID: neet-ug-

An electron of mass with an initial velocity enters an electric field at . If is its de-Broglie wavelength initially,. then its de-Broglie wavelength at time is

1

2

3

4

30

PYQ 2018

medium

physics ID: neet-ug-

When the light of frequency (where is threshold frequency), is incident on a metal plate, the maximum velocity of electrons emitted is . When the frequency of the incident radiation is increased to, the maximum velocity of electrons emitted from the same plate is . The ratio of to is

1

2:01

2

1:02

3

4:01

4

1:04

31

PYQ 2019

easy

physics ID: neet-ug-

An electron is accelerated through a potential difference of 10,000 V. Its de Broglie wavelength is. (nearly): (mt. = kg)

32

PYQ 2020

medium

physics ID: neet-ug-

An electron is accelerated from rest through a potential difference of V volt. If the de Broglie wavelength of the electron is, the potential difference is :

1

V

2

V

3

V

4

V

33

PYQ 2020

medium

physics ID: neet-ug-

Light of frequency 1.5 times the threshold frequency is incident on a photosensitive material. What will be the photoelectric current if the frequency is halved and intensity is doubled?

1

doubled

2

four times

3

one-fourth

4

zero