Quiz - physics - Dual Nature of Radiation and Matter-PYQ

Q1. A beam of cathode rays is subjected to crossed electric (E) and magnetic fields (B). The fields are adjusted such that the beam is not deflected. The specific charge of the cathode rays is given by \left(E\over{VB}\right) where V is the potential difference between cathode and anode) Source: orcusprep.in

NEET 2010

hard

$\frac{B^2}{2 V E^2}$

$\frac{V^2 B^2}{2 E^2}$

$\frac{2 V E^2}{B^2}$

$\frac{E^2}{2 V B^2}$

Q2. In the phenomenon of electric discharge through gases at low pressure, the coloured glow in the tube appears as a result of Source: orcusprep.in

NEET 2008

easy

collisions between the charged particles emitted from the cathode and the atoms of the gas

collision between different electrons of the atoms of the gas

excitation of electrons in the atoms

collision between the atoms of the gas.

Q3. In a discharge tube ionization of enclosed gas is produced due to collisions between Source: orcusprep.in

NEET 2006

easy

neutral gas atoms/molecules

positive ions and neutral atoms/molecules

negative electrons and neutral atoms/molecules

photons and neutral atoms/molecules.

Q4. J.J. Thomson’s cathode-ray tube experiment demonstrated that Source: orcusprep.in

NEET 2003

easy

cathode rays are streams of negatively charged ions

all the mass of an atom is essentially in the nucleus

the e/m of electrons is much greater than the e/m of protons

the e/m ratio of the cathode-ray particles changes when a different gas is placed in the discharge tube

Q5. Which of the following is not the property of cathode rays ? Source: orcusprep.in

NEET 2002

easy

It produces heating effect.

It does not deflect in electric field.

It casts shadow.

It produces fluorescence.

Q6. Who evaluated the mass of electron indirectly with help of charge? Source: orcusprep.in

NEET 2000

easy

Thomson

Millikan

Rutherford

Newton

Q7. In a discharge tube at 0.02 mm, there is formation of Source: orcusprep.in

NEET 1996

easy

Crooke’s dark space

Faraday’s dark space

both space partly

none of these.

Q8. In which of the following, emission of electrons does not take place Source: orcusprep.in

NEET 1990

easy

thermionic emission

X-rays emission

photoelectric emission

secondary emission

Q9. Thermions are Source: orcusprep.in

NEET 1988

easy

protons

electrons

photons

positrons.

Q10. A source of light is placed at a distance of 50 cm from a photo cell and the stopping potential is found to be $V_0$. If the distance between the light source and photo cell is made 25 cm, the new stopping potential will be : Source: orcusprep.in

Karnataka NEET 2013

medium

$\tfrac{V_0}{2}$

$V_0$

$4V_0$

$2V_0$

Q11. Photoelectric emission occurs only when the incident light has more than a certain minimum Source: orcusprep.in

NEET 2011

easy

power

wavelength

intensity

frequency

Q12. In photoelectric emission process from a metal of work function 1.8 eV, the kinetic energy of most energetic electrons is 0.5 eV. The corresponding stopping potential is Source: orcusprep.in

NEET 2011

easy

1.8 V

1.3 V

0.5 V

2.3 V

Q13. A 5 watt source emits monochromatic light of wavelength 5000 Å. When placed 0.5 m away, it liberates photoelectrons from a photosensitive metallic surface. When the source is moved to a distance of 1.0 m, the number of photoelectrons liberated will be reduced by a factor of Source: orcusprep.in

NEET 2007

medium

8

16

2

4

Q14. A photocell employs photoelectric effect to convert Source: orcusprep.in

NEET 2006

easy

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

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

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

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

Q15. A photoelectric cell is illuminated by a point source of light 1 m away. When the source is shifted to 2 m then Source: orcusprep.in

NEET 2003

medium

each emitted electron carries one quarter of the initial energy

number of electrons emitted is half the initial number

each emitted electron carries half the initial energy

number of electrons emitted is a quarter of the initial number.

Q16. When ultraviolet rays incident on metal plate then photoelectric effect does not occur, it occurs by incidence of Source: orcusprep.in

NEET 2002

easy

infrared rays

X-rays

radio wave

micro wave.

Q17. A photo-cell is illuminated by a source of light, which is placed at a distance d from the cell. If the distance become d/2, then number of electrons emitted per second will be Source: orcusprep.in

NEET 2001

easy

remain same

four times

two times

one-fourth.

Q18. As the intensity of incident light increases Source: orcusprep.in

NEET 1999

easy

kinetic energy of emitted photoelectrons increases

photoelectric current decreases

photoelectric current increases

kinetic energy of emitted photoelectrons decreases.

Q19. Which of the following statement is correct? Source: orcusprep.in

NEET 1997

easy

The photocurrent increases with intensity of light.

The stopping potential increases with increase of incident light.

The current in photocell increases with increasing frequency.

The photocurrent is proportional to the applied voltage.

Q20. Number of ejected photoelectrons increases with increase Source: orcusprep.in

NEET 1993

easy

in intensity of light

in wavelength of light

in frequency of light

never.

Q21. The cathode of a photoelectric cell is changed such that the work function changes from $W_1$ to $W_2$ $(W_2 > W_1)$. If the current before and after changes are $I_1$ and $I_2$, all other conditions remaining unchanged, then (assuming $h\nu > W_2$). Source: orcusprep.in

NEET 1992

medium

$I_1$ = $I_2$

$I_1$< $I_2$

$I_1$ > $I_2$

$I_1$< $I_2$ < 2x$I_1$

Q22. When monochromatic radiation of intensity I falls on a metal surface, the number of photoelectrons and their maximum kinetic energy are N and T respectively. If the intensity of radiation is 2I, the number of emitted electrons and their maximum kinetic energy are respectively Source: orcusprep.in

NEET Mains 2010

medium

N and 2T

2N and T

2N and 2T

N and T

Q23. The number of photoelectrons emitted for light of a frequency $$ \nu \; (\text{higher than the threshold frequency } \nu_0) $$ is proportional to Source: orcusprep.in

NEET 2009

easy

threshold frequency ($\nu_0$)

intensity of light

frequency of light ($\nu$)

$\nu - \nu_0$

Q24. 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? Source: orcusprep.in

NEET 2020

medium

Doubled

Four times

One-fourth

Zero

Q25. The work function of a photosensitive material is 4.0 eV. The longest wavelength of light that can cause photon emission from the substance is (approximately) Source: orcusprep.in

Odisha NEET 2019

easy

3100 nm

966 nm

31 nm

310 nm

Q26. When the light of frequency $2
u_0$ (where $
u_0$ is threshold frequency), is incident on a metal plate, the maximum velocity of electrons emitted is $v_1$. When the frequency of the incident radiation is increased to $5
u_0$, the maximum velocity of electrons emitted from the same plate is $v_2$. The ratio of $v_1$ to $v_2$ is Source: orcusprep.in

NEET 2018

medium

1 : 2

1 : 4

4 : 1

2 : 1

Q27. The photoelectric threshold wavelength of silver is $3250 x 10^{-10}$ m. The velocity of the electron ejected from a silver surface by ultraviolet light of wavelength $2536 x 10^{-10}$ m is [Given $h = 4.14 x 10^{-15}$ eV s and $c = 3 x 10^8$ m s$^{-1}$] Source: orcusprep.in

NEET 2017

hard

≈ $0.6 x 10^6$ m s$^{-1}$

≈ $61 x 10^3$ m s$^{-1}$

≈ $0.3 x 10^6$ m s$^{-1}$

≈ $6 x 10^5$ m s$^{-1}$

Q28. 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 is Source: orcusprep.in

NEET-II 2016

medium

+3 V

+4 V

-1 V

-3 V

Q29. When a metallic surface is illuminated with radiation of wavelength $\lambda$, the stopping potential is $V$. If the same surface is illuminated with radiation of wavelength $2\lambda$, the stopping potential is $\frac{V}{4}$. The threshold wavelength for the metallic surface is Source: orcusprep.in

NEET-I 2016

hard

$\frac{5}{2}\lambda$

$3\lambda$

$4\lambda$

$5\lambda$

Q30. A photoelectric surface is illuminated successively by monochromatic light of wavelength $\lambda$ and $\lambda/2$. 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) Source: orcusprep.in

NEET 2015

medium

$\frac{2hc}{\lambda}$

$\frac{hc}{3\lambda}$

$\frac{hc}{2\lambda}$

$\frac{hc}{\lambda}$

Q31. A certain metallic surface is illuminated with monochromatic light of wavelength, $\lambda$. The stopping potential for photoelectric current for this light is $3V_0$. If the same surface is illuminated with light of wavelength $2\lambda$, the stopping potential is $V_0$. The threshold wavelength for this surface for photoelectric effect is Source: orcusprep.in

2015 Cancelled

medium

$\frac{\lambda}{4}$

$\frac{\lambda}{6}$

$6\lambda$

$4\lambda$

Q32. When the energy of the incident radiation is increased by 20\%, 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 Source: orcusprep.in

NEET 2014

medium

0.65 eV

1.0 eV

1.3 eV

1.5 eV

Q33. For photoelectric emission from certain metal the cutoff frequency is $
u$. If radiation of frequency $2
u$ impinges on the metal plate, the maximum possible velocity of the emitted electron will be (m is the electron mass) Source: orcusprep.in

NEET 2013

medium

$2\sqrt{\frac{h\nu}{m}}$

$\sqrt{\frac{2h\nu}{m}}$

$\sqrt{\frac{h\nu}{m}}$

$\sqrt{\frac{h\nu}{2m}}$

Q34. Two radiations of photons energies 1 eV and 2.5 eV, successively illuminate a photosensitive metallic surface of work function 0.5 eV. The ratio of the maximum speeds of the emitted electrons is Source: orcusprep.in

NEET Mains 2012, 2011

easy

1 : 4

1 : 2

1 : 1

1 : 5

Q35. The threshold frequency for a photosensitive metal is $3.3 x 10^{14}$ Hz. If light of frequency $8.2 x 10^{14}$ Hz is incident on this metal, the cut-off voltage for the photoelectron emission is nearly Source: orcusprep.in

NEET Mains 2011

medium

1 V

2 V

3 V

5 V

Q36. The potential difference that must be applied to stop the fastest photoelectrons emitted by a nickel surface, having work function 5.01 eV, when ultraviolet light of 200 nm falls on it, must be Source: orcusprep.in

NEET 2010

medium

2.4 V

-1.2 V

-2.4 V

1.2 V

Q37. The work function of a surface of a photosensitive material is 6.2 eV. The wavelength of the incident radiation for which the stopping potential is 5 V lies in the Source: orcusprep.in

NEET 2008

medium

Infrared region

X-ray region

Ultraviolet region

Visible region.

Q38. When photons of energy $h
u$ fall on an aluminium plate (of work function $E_0$), photoelectrons of maximum kinetic energy K are ejected. If the frequency of radiation is doubled, the maximum kinetic energy of the ejected photoelectrons will be Source: orcusprep.in

NEET 2006

medium

$K + h\nu$

$K + E_0$

$2K$

$K$

Q39. The work functions for metals A, B and C are respectively 1.92 eV, 2.0 eV and 5 eV. According to Einstein’s equation the metals which will emit photoelectrons for a radiation of wavelength 4100 Å is/are Source: orcusprep.in

NEET 2005

medium

A only

A and B only

all the three metals

none.

Q40. A photosensitive metallic surface has work function, $h
u_0$. If photons of energy $2h
u_0$ fall on this surface, the electrons come out with a maximum velocity of $4 x 10^6$ m/s. When the photon energy is increased to $5h
u_0$, then maximum velocity of photoelectrons will be Source: orcusprep.in

NEET 2005

hard

$2 x 10^7$ m/s

$2 x 10^6$ m/s

$8 x 10^6$ m/s

$8 x 10^5$ m/s

Q41. The value of Planck’s constant is Source: orcusprep.in

NEET 2002

easy

6.63 $x 10^{-34}$ J/sec

6.63 $x 10^{-34}$ kg m$^2$/sec

6.63 $x 10^{-34}$ kg m$^2$

6.63 $x 10^{-34}$ J sec

Q42. By photoelectric effect, Einstein proved Source: orcusprep.in

NEET 2000

easy

$E = h\nu$

$K.E. = \frac{1}{2}mv^2$

$E = mc^2$

$E_n = -\frac{Rhc}{n^2}$

Q43. The photoelectric work function for a metal surface is 4.125 eV. The cut-off wavelength for this surface is Source: orcusprep.in

NEET 1999

easy

3000 Å

2062.5 Å

4125 Å

6000 Å

Q44. In a photo-emissive cell, with exciting wavelength $\lambda$, the fastest electron has speed $v$. If the exciting wavelength is changed to $\frac{3}{4}\lambda$, the speed of the fastest emitted electron will be Source: orcusprep.in

NEET 1998

hard

less than $v(4/3)^{1/2}$

$v(4/3)^{1/2}$

$v(3/4)^{1/2}$

greater than $v(4/3)^{1/2}$

Q45. 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? Source: orcusprep.in

NEET 1993

medium

1 : 2

2 : 1

4 : 1

1 : 4

Q46. Photoelectric work function of a metal is 1 eV. Light of wavelength $\lambda = 3000$ Å falls on it. The photo electrons come out with a maximum velocity Source: orcusprep.in

NEET 1991

medium

$10^1$ metres/sec

$10^2$ metres/sec

$10^4$ metres/sec

$10^6$ metres/sec

Q47. Ultraviolet radiations of 6.2 eV falls on an aluminium surface. Kinetic energy of fastest electron emitted is (work function = 4.2 eV) Source: orcusprep.in

NEET 1989

easy

$3.2 x 10^{-21}$ J

$3.2 x 10^{-19}$ J

$7 x 10^{-25}$ J

$9 x 10^{-32}$ J

Q48. The threshold frequency for photoelectric effect on sodium corresponds to a wavelength of 5000 Å. Its work function is Source: orcusprep.in

NEET 1988

easy

$4 x 10^{-19}$ J

$1$ J

$2 x 10^{-19}$ J

$3 x 10^{-19}$ J

Q49. A 200 W sodium street lamp emits yellow light of wavelength 0.6 mm. Assuming it to be 25% efficient in converting electrical energy to light, the number of photons of yellow light it emits per second is Source: orcusprep.in

NEET 2012

medium

$1.5 x 10^{20}$

$6 x 10^{18}$

$62 x 10^{20}$

$3 x 10^{19}$

Q50. A source $S_1$ is producing, $10^{15}$ photons per second of wavelength 5000 Å. Another source $S_2$ is producing $1.02 x 10^{15}$ photons per second of wavelength 5100 Å. Then, (power of $S_2$)/(power of $S_1$) is equal to Source: orcusprep.in

NEET 2010

medium

1.00

1.02

1.04

0.98

Q51. Monochromatic light of wavelength 667 nm is produced by a helium neon laser. The power emitted is 9 mW. The number of photons arriving per second on the average at a target irradiated by this beam is Source: orcusprep.in

NEET 2009

easy

$3 x 10^{16}$

$9 x 10^{15}$

$3 x 10^{19}$

$9 x 10^{17}$

Q52. Monochromatic light of frequency $6.0 x 10^{14}$ Hz is produced by a laser. The power emitted is $2 x 10^{-3}$ W. The number of photons emitted, on the average, by the source per second is Source: orcusprep.in

NEET 2007

easy

$5 x 10^{16}$

$5 x 10^{17}$

$5 x 10^{14}$

$5 x 10^{15}$

Q53. The momentum of a photon of energy 1 MeV in kg m/s will be Source: orcusprep.in

NEET 2006

easy

$5 x 10^{-22}$

$0.33 x 10^6$

$7 x 10^{-24}$

$10^{-22}$

Q54. A 200 W sodium street lamp emits yellow light of wavelength 0.6 mm. Assuming it to be 25% efficient in converting electrical energy to light, the number of photons of yellow light it emits per second is Source: orcusprep.in

NEET 2012

medium

1.5 $x 10^{20}$

6 $x 10^{18}$

62 $x 10^{20}$

3 $x 10^{19}$

Q55. A source $S_1$ is producing, $10^{15}$ photons per second of wavelength 5000 Å. Another source $S_2$ is producing $1.02 x 10^{15}$ photons per second of wavelength 5100 Å. Then, (power of $S_2$)/(power of $S_1$) is equal to Source: orcusprep.in

NEET 2010

medium

1.00

1.02

1.04

0.98

Q56. Monochromatic light of wavelength 667 nm is produced by a helium neon laser. The power emitted is 9 mW. The number of photons arriving per second on the average at a target irradiated by this beam is Source: orcusprep.in

NEET 2009

easy

3 $x 10^{16}$

9 $x 10^{15}$

3 $x 10^{19}$

9 $x 10^{17}$

Q57. Monochromatic light of frequency 6.0 $x 10^{14}$ Hz is produced by a laser. The power emitted is $2 x 10^{-3}$ W. The number of photons emitted, on the average, by the source per second is Source: orcusprep.in

NEET 2007

easy

5 $x 10^{16}$

5 $x 10^{17}$

5 $x 10^{14}$

5 $x 10^{15}$

Q58. The momentum of a photon of energy 1 MeV in kg m/s will be Source: orcusprep.in

NEET 2006

easy

5 $x 10^{-22}$

0.33 $x 10^6$

7 $x 10^{-24}$

10^{-22}

Q59. If a photon has velocity c and frequency $
u$, then which of the following represents its wavelength? Source: orcusprep.in

NEET 1996

easy

$\frac{h}{c\nu^2}$

$h\nu$

$\frac{hc}{E}$

$\frac{h}{c\nu}$

Q60. The velocity of photons is proportional to (where $
u$ = frequency) Source: orcusprep.in

NEET 1996

medium

$1/\nu$

$\nu^2$

$\nu$

The velocity of a photon is a constant c, independent of its frequency

Q61. Momentum of photon of wavelength $\lambda$ is Source: orcusprep.in

NEET 1993

easy

$\frac{h\nu}{c}$

zero

$\frac{h\lambda^2}{c}$

$\frac{h}{\lambda}$

Q62. The wavelength of a 1 keV photon is $1.24 x 10^{-9}$ m. What is the frequency of 1 MeV photon? Source: orcusprep.in

NEET 1991

medium

1.24 $x 10^{15}$

2.4 $x 10^{20}$

1.24 $x 10^{18}$

2.4 $x 10^{23}$

Q63. A radio transmitter operates at a frequency 880 kHz and a power of 10 kW. The number of photons emitted per second is Source: orcusprep.in

NEET 1990

medium

1.72 $x 10^{31}$

1.327 $x 10^{25}$

1.327 $x 10^{37}$

1.327 $x 10^{45}$

Q64. The momentum of a photon of an electromagnetic radiation is $3.3 x 10^{-29}$ kg m s$^{-1}$. What is the frequency of the associated waves? [h = $6.6 x 10^{-34}$ J s ; c = $3 x 10^8$ m s$^{-1}$] Source: orcusprep.in

NEET 1990

easy

1.5 $x 10^{13}$ Hz

7.5 $x 10^{12}$ Hz

6 $x 10^3$ Hz

3 $x 10^3$ Hz

Q65. The energy of a photon of wavelength $\lambda$ is Source: orcusprep.in

NEET 1988

easy

$hc\lambda$

$\frac{hc}{\lambda}$

$\frac{\lambda}{hc}$

$\frac{\lambda h}{c}$

Q66. An electron is accelerated from rest through a potential difference of V volt. If the de Broglie wavelength of the electron is $1.227 x 10^{-2}$ nm, the potential difference is Source: orcusprep.in

NEET 2020

medium

10 V

$10^2$ V

$10^3$ V

$10^4$ V

Q67. An electron is accelerated through a potential difference of 10,000 V. Its de Broglie wavelength is, (nearly) (me = $9 x 10^{-31}$ kg) Source: orcusprep.in

NEET 2019

easy

12.2 nm

12.2 $x 10^{-13}$ m

12.2 $x 10^{-12}$ m

12.2 $x 10^{-14}$ m

Q68. An electron of mass m with an initial velocity $\vec{v} = v_0\hat{i} (v_0 > 0)$ enters an electric field $\vec{E} = -E_0\hat{i} (E_0 = \text{constant} > 0)$ at t = 0. If $\lambda_0$ is its de-Broglie wavelength initially, then its de-Broglie wavelength at time t is Source: orcusprep.in

NEET 2018

medium

$\lambda_0 \left(1 + \frac{eE_0}{mv_0}t\right)^{-1}$

$\lambda_0 \left(1 + \frac{eE_0t}{mv_0}\right)$

$\lambda_0 t$

$\lambda_0$

Q69. The de-Broglie wavelength of a neutron in thermal equilibrium with heavy water at a temperature T (kelvin) and mass m, is Source: orcusprep.in

NEET 2017

medium

$\frac{h}{\sqrt{3mkT}}$

$\frac{2h}{\sqrt{3mkT}}$

$\frac{2h}{\sqrt{mkT}}$

$\frac{h}{\sqrt{mkT}}$

Q70. Electrons of mass m with de-Broglie wavelength $\lambda$ fall on the target in an X-ray tube. The cutoff wavelength ($\lambda_0$) of the emitted X-ray is Source: orcusprep.in

NEET-II 2016

hard

$\lambda_0 = \frac{2mc\lambda^2}{h}$.

$\lambda_0 = \frac{h}{mc}$

$\lambda_0 = \frac{2m^2c^2\lambda^2}{h}$

$\lambda_0 = \lambda$

Q71. An electron of mass m and a photon have same energy E. The ratio of de-Broglie wavelengths associated with them is Source: orcusprep.in

NEET-I 2016

hard

$c\left(\frac{2m}{E}\right)^{1/2}$

$\frac{1}{c}\left(\frac{E}{2m}\right)^{1/2}$

$\frac{1}{c}\left(\frac{E}{2m}\right)^{-1/2}$

$\left(\frac{E}{2m}\right)^{1/2}$

Q72. 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 Source: orcusprep.in

NEET 2015

hard

$\ge 2.8 x 10^{-9}$ m

$\le 2.8 x 10^{-12}$ m

$< 2.8 x 10^{-10}$ m

$< 2.8 x 10^{-9}$ m

Q73. If the kinetic energy of the particle is increased to 16 times its previous value, the percentage change in the de Broglie wavelength of the particle is Source: orcusprep.in

NEET 2014

easy

25

75

60

50

Q74. The wavelength $\lambda_e$ of an electron and $\lambda_p$ of a photon of same energy E are related by Source: orcusprep.in

NEET 2013

hard

$\lambda_p \propto \lambda_e$

$\lambda_p \propto \frac{1}{\lambda_e}$

$\lambda_p \propto \lambda_e^2$

$\lambda_p \propto \lambda_e^{-1}$

Q75. The de-Broglie wavelength of neutrons in thermal equilibrium at temperature T is Source: orcusprep.in

Karnataka NEET 2013

hard

30.8$/$T$^{1/2}$ Å

0.308$/$T$^{1/2}$ Å

0.0308$/$T$^{1/2}$ Å

30.8$/$T$^{1/2}$ Å

Q76. An $\alpha$-particle moves in a circular path of radius 0.83 cm in the presence of a magnetic field of $0.25$ Wb/m$^{2}$. The de Broglie wavelength associated with the particle will be Source: orcusprep.in

NEET 2012

medium

1 Å

0.1 Å

10 Å

0.01 Å

Q77. If the momentum of an electron is changed by P, then the de Broglie wavelength associated with it changes by 0.5%. The initial momentum of electron will be Source: orcusprep.in

Mains 2012

medium

200P

400P

P/200

100P

Q78. Electrons used in an electron microscope are accelerated by a voltage of 25 kV. If the voltage is increased to 100 kV then the de-Broglie wavelength associated with the electrons would Source: orcusprep.in

NEET 2011

easy

increase by 2 times

decrease by 2 times

decrease by 4 times

increase by 4 times.

Q79. A particle of mass 1 mg has the same wavelength as an electron moving with a velocity of $3 x 10^6$ m s$^{-1}$. The velocity of the particle is (mass of electron = $9.1 x 10^{-31}$ kg) Source: orcusprep.in

NEET 2008

medium

3 $x 10^{-31}$ m s$^{-1}$

2.7 $x 10^{-21}$ m s$^{-1}$

2.7 $x 10^{-18}$ m s$^{-1}$

9 $x 10^{-2}$ m s$^{-1}$

Q80. If particles are moving with same velocity, then which has maximum de Broglie wavelength? Source: orcusprep.in

NEET 2002

easy

proton

$\alpha$-particle

neutron

$\beta$-particle

Q81. Which one among the following shows particle nature of light? Source: orcusprep.in

NEET 2001

easy

photoelectric effect

interference

refraction

polarization.

Q82. When a proton is accelerated through 1 V, then its kinetic energy will be Source: orcusprep.in

NEET 1999

easy

1 eV

13.6 eV

1840 eV

0.54 eV

Q83. The kinetic energy of an electron, which is accelerated in the potential difference of 100 volts, is Source: orcusprep.in

NEET 1997

easy

416.6 cal

6.636 cal

1.602 $x 10^{-17}$ J

1.6 $x 10^4$ J

Q84. An electron beam has a kinetic energy equal to 100 eV. Find its wavelength associated with a beam, if mass of electron = $9.1 x 10^{-31}$ kg and 1 eV = $1.6 x 10^{-19}$ J. (Planck’s constant = $6.6 x 10^{-34}$ Js) Source: orcusprep.in

NEET 1996

easy

24.6 Å

0.12 Å

1.2 Å

6.3 Å

Q85. An electron of mass m and charge e is accelerated from rest through a potential difference V in vacuum. Its final velocity will be Source: orcusprep.in

NEET 1996

easy

$\sqrt{\frac{2eV}{m}}$

$\sqrt{\frac{eV}{m}}$

$\frac{eV}{2m}$

$\frac{eV}{m}$

Q86. An electron of mass m, when accelerated through a potential difference V, has de Broglie wavelength $\lambda$. The de Broglie wavelength associated with a proton of mass M accelerated through the same potential difference, will be Source: orcusprep.in

NEET 1995

easy

$\lambda\sqrt{\frac{M}{m}}$

$\lambda\sqrt{\frac{m}{M}}$

$\lambda\frac{M}{m}$

$\lambda\frac{m}{M}$

Q87. If we consider electrons and photons of same wavelength, then they will have same Source: orcusprep.in

NEET 1995

medium

momentum

angular momentum

energy

velocity.

Q88. The de Broglie wave corresponding to a particle of mass m and velocity v has a wavelength associated with it Source: orcusprep.in

NEET 1989

easy

$\frac{h}{mv}$

$hmv$

$\frac{mh}{v}$

$\frac{m}{hv}$

Q89. In the Davisson and Germer experiment, the velocity of electrons emitted from the electron gun can be increased by Source: orcusprep.in

NEET 2011

easy

increasing the potential difference between the anode and filament

increasing the filament current

decreasing the filament current

decreasing the potential difference between the anode and filament.

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Physics - Dual Nature of Radiation and Matter-PYQ

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Physics - Dual Nature of Radiation and Matter-PYQ

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