Q.1.
A photon of energy 8eV is incident on a metal surface of threshold frequency 1.6×1015 Hz. The maximum kinetic energy of photoelectrons emitted is ... [ GUJCET 2008]
-
33%
a) 2.8 eV
-
33%
b) 4.2 eV
-
33%
c)0.8 eV
-
0%
d)1.4eV
Q.2.
The photoelectric threshold wavelength for potassium having workfunction of 2eV is ... [GUJCET 2008]
-
0%
a) 310.7 nm
-
100%
b) 1240 nm
-
0%
c)618.7 nm
-
0%
d)618.7 mm
Q.3.
Ultraviolet light of wavelength 200 nm is incident on polished surface of Fe. Work function of the surface is 4.71 eV. What will be the stopping potential? [GUJCET 2008]
-
33%
a) 2.5 V
-
0%
b) 1.5 V
-
33%
c) 0.5 V
-
33%
d) none of above
Q.4.
The number of photons of wavelength 660 nm emitted per second by an electric bulb of 60W is [ GUJCET 2008]
-
0%
a)2 × 1020
-
67%
b) 2 × 10-20
-
33%
c)1.5 × 1020
-
0%
d)3 × 1020
Q.5.
An alpha particle and a deuteron are moving with velocities v and 2v respectively. What will be the ratio of their de_broglie wavelengths? [ GUJCET 2008]
-
50%
a) 2:1
-
50%
b) 1:√2
-
0%
c)√2 : 1
-
0%
d)1 : 1
Q.6.
In photoelectric effect, the threshold wavelength of sodium is 5000Å. Find its work function [ GUJCET 2009]
-
0%
a) 7.5 eV
-
0%
b) 2.5 eV
-
100%
c)10 eVV
-
0%
d)5 eV
Q.7.
If the linear momentum of a particle is 2.2 × 104 kgm/s then what will be its de-Broglie wavelength [ GUJCET 2009]
-
0%
a) 3 × 10-29 m
-
50%
b) 3 × 10-29 nm
-
0%
c) 6 × 10-29 m
-
50%
d) 6 × 10-29 nm
Q.8.
Sodium and Copper have workfunction 2.3eV and 4.5eV respectively. The ratio their threshold wavelength is nearest to ... [AIEEE2002]
-
0%
a)1 : 2
-
50%
b) 4 :1
-
50%
c)2 : 1
-
0%
d)1 : 4
Q.9.
Formation of covalent bonds in compound exhibits .... of electron [ AIEEE 2002]
-
0%
a) wave nature
-
0%
b) particle nature
-
100%
c)both wave and particle nature
-
0%
d)none of these
Q.10.
According to Einstein's photoelectric equation, the plot of the kinetic energy of the emitted photoelectrons from metal vs frequency of the incident radiation gives straight line whose slope .... [ AIEEE 2004]
-
0%
a)depends on the nature of the material used
-
100%
b) depends on the intensity of the radiation
-
0%
c)depends both on the intensity of the radiation and the metal used
-
0%
d)is same for all metals and independent of the intensity of radiation
Q.11.
Time taken by a photoelectron to come out after the photon strikes is approximately ... [ AIEEE 2006]
-
0%
a) 10-4 s
-
0%
b) 10-10s
-
100%
c) 10-16s
-
0%
d) 10-1 s
Q.12.
If a strong diffraction peak is observed when electrons are incident at an angle of i from the normal to crystal planes with distance d between them ( as shown) de-Broglie wavelength of electrons can be calculates by the relationship... ( n is an integer) [ AIEEE 2008]
-
50%
a) dsin i=n λ
-
50%
b) 2dcos i=n λ
-
0%
c)2dsin i=n λ
-
0%
d)dcos i=nλ
Q.13.
Electrons accelerated by potential V are diffracted from a crystal ( as shown). If d=1Å and i=30° V should be
-
50%
a) 2000 V
-
0%
b) 50 V
-
50%
c)500 V
-
0%
d)1000 V
Explanation
Q.14.
The threshold frequency for a metallic surface corresponds to an energy of 6.2eV and the stopping potential for a radiation incident on this surface is 5V. The incident radiation lies in the .... [ AIEEE 2006]
-
0%
a) UV region
-
0%
b) IR region
-
100%
c)visible region
-
0%
d)X -ray region
Q.15.
The cathode of a photoelecric cell is changed such that the work function changes from W1 to W2 ( W2 > WIf the current before and after changes are I1 and I2, all other conditions remaining unchanged, then ....( Assume hf > W2)[ CPMT 1992]
-
0%
a) I1=I2
-
50%
b) I1 < I2
-
50%
c) I1 > I2
-
0%
d) I1 < I2 < 2I1
Q.16.
When light of wavelength 300nm falls on a photoelectric emitter, photoelectrons are liberated. For another emitter, however, light of 600nm wavelength is sufficient for creating photoemission. What is the ratio of the work functions of the to emitters? [ CPMT 1993]
-
0%
a)1 : 2
-
50%
b) 2 : 1
-
50%
c)4 : 1
-
0%
d)1 : 4
Q.17.
A electron of mass m, when accelerated through a potential difference V, has de-Broglie wavelength λ. The de-Broglie wavelength associated with a proton of mass M accelerated through the same potential difference, will be ... [CPMT 1995]
-
0%
a) λ(M/m)
-
0%
b) λ(m/M)
-
100%
c) λ√(M/m)
-
0%
d)λ√(m/M)
Explanation
Q.18.
If a photon has a velocity c and frequency f, then which of the following represents its wavelength? [ CPMT 1996]
-
0%
a) hf/c
-
0%
b) hf
-
50%
c)hc/E
-
50%
d)hf/c2
Q.19.
In a photo emissive cell with exciting wavelength λ, the fastest electron has speed v. If the exciting wavelength is changed to 3λ/4, the speed of the fastest emitted electron will be ... [ CPMT 1998]
-
0%
a) v(3/4)1/2
-
0%
b) v(4/3)1/2
-
0%
c) less than v(4/3)1/2
-
100%
d) greater than v(4/3)1/2
Q.20.
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 ...[ CPMT 2001]
-
50%
a)remains same
-
50%
b) four times
-
0%
c)two times
-
0%
d)one-fourth
Q.21.
Particle nature of and wave nature of electromagnetic waves and electrons can be represented by ..[ [AIIMS 2000]
-
0%
a) photo electricity and electron microscopy
-
0%
b) light is refracted and diffracted
-
50%
c)X-ray is diffracted, reflected by thick metal sheet
-
50%
d)electrons have small mass, deflected by the metal sheet
Q.22.
In an electron microscope the accelerating voltage is increased from 20kV to 80 kV, the resolving power of the microscope will become..... [ AIIMS 2000]
-
0%
a) 2R
-
50%
b) R/2
-
50%
c)4R
-
0%
d)3R
Q.23.
The speed of an electron having wavelength of 10-10m is .... [ AIIMS 2002]
-
0%
a) 4.24 × 106 m/s
-
50%
b) 5.25 ×106 m/s
-
0%
c) 6.25 × 106 m/s
-
50%
d) 7.25 × 106 m/s
Q.24.
A proton is about 1840 times heavier than an electron. When it is accelerated by a potential difference of 1kV, its kinetic energy will be ....[ AIIMS 2003]
-
0%
a)1840 keV
-
50%
b) (1/1840) keV
-
50%
c)1 keV
-
0%
d)920 keV
Q.25.
When a beam of light is used to determine the position of an object, the maximum accuracy is achieved if light is ... [ AIIMS 2003]
-
0%
a) polarised
-
0%
b) of longer wavelength
-
50%
c)of shorter wavelength
-
50%
d)of higher intensity
Q.26.
If the momentum of a particle is doubled then its d-Broglie wavelength will become... [ AFMC 1998]
-
0%
a) unchanged
-
50%
b) four times
-
0%
c)two times
-
50%
d)half time
Q.27.
X-ray region lies between [ JIPMER 1998]
-
0%
a) short radio waves and visible light
-
0%
b) visible light and ultraviolet region
-
50%
c) gamma rays and ultraviolet rays
-
50%
d) short radio waves and long radio waves
Q.28.
The wavelenght λ of the Kα X-ray line of an anticathode element of atomic number z is nearly proportional to ...[ MPPMT 1987]
-
0%
a)Z2
-
0%
b) (Z - 1)2
-
50%
c)1/Z-1
-
50%
d)1 / (Z-1)2
Q.29.
Both γ-rays and X-rays are electromagnetic waves. the basic difference in them is [ raj.PMT 1997]
-
0%
a) The production of X-rays is a nuclear property whereas the production of γ-rays is an atomic property
-
100%
b) The production of X-rays is an atomic property whereas the production of γ-rays is a nuclear property
-
0%
c)γ rays have less frequency than X-rays
-
0%
d)the velocity of γ rays is more than that of X-rays
Q.30.
X-rays passing through a strong uniform magnetic field [ CPMT 1998]
-
0%
a) get deflected in the direction of the field
-
0%
b) get deflected in the direction opposite to that of field
-
100%
c)get deflected in the direction perpendicular to that of the field
-
0%
d)do not get deflected at all