Q.1.
in photoelectric effect work function of any metal is 2.5eV. Emitted electrons are stopped by the potential of 1.5volt then
-
40%
a)energy of incident photons is 4eV
-
31%
b) energy of incident photons is 1eV
-
14%
c)photoelectric current increases when we use photos of high frequency
-
14%
d)none of the above
Q.2.
If the wavelength of incident light changes from 4000Å to 3600Å, change in stopping potential will be
-
40%
a) +0.35V
-
36%
b) -0.35V
-
20%
c)+0.4V
-
4%
d)-0.4 V
Q.3.
The slope of the graph Kmax Vs f in photo electric effect is
-
21%
a) h
-
36%
b) h/e
-
18%
c)he
-
25%
d)e/h
Q.4.
In photocell, energy conversion is from...
-
42%
a) chemical to electrical
-
17%
b) mechanical to electrical
-
38%
c)optical to electrical
-
4%
d)magnetic to electrical
Q.5.
The photoelectric currents at distance r1 and r2 of a light source from a photocell are I1 and I2 respectively. What is the value of I2 / I1 ?
-
15%
a) r1 / r2
-
30%
b) r2 / r1
-
25%
c) (r1 / r2)2
-
30%
d) (r2 / r1)2
Q.6.
Ratio of momentum of 105eV, X-ray photon (P) with that of 105eV electron (P')
-
13%
a) P'/P=1/2
-
53%
b) P'/P=16/5
-
20%
c) P'/P=1/5
-
13%
d) P'/P=5/1
Q.7.
An atom emits a photon of wavelength 1 Å. The energy of recoil of the atom will be ( mass of atom=1 amu)
-
27%
a) 1.304 × 10-20 J
-
40%
b) 1.304 eV
-
33%
c) 1.532 × 10-19J
-
0%
d) 1.532 eV
Explanation
Q.8.
The de-Broglie wavelength of a proton and alpha particle is same, the ratio of their velocities is
-
14%
a)1:4
-
36%
b) 1:2
-
7%
c)2:1
-
43%
d)4:1
Q.9.
The energy of an electron having de_broglie wavelength λ is
-
21%
a) h/2m
-
29%
b) h2/2mλ
-
21%
c)h2/2λ2
-
29%
d)h2/2mλ2
Q.10.
If the momentum of a particle is doubled, then its de-Broglie wavelength will become.. [ AFMC 1997]
-
15%
a)unchanged
-
31%
b) four times
-
15%
c)two times
-
38%
d)half times
Q.11.
The threshold frequency for a photosensitive metal is 3.3×1014Hz. If light of frequency 8.2×1014Hz is incident on this metal. the cut-off voltage for the photoelectric emission is nearly [ CBSE-PMT 2011]
-
7%
a)2V
-
64%
b) 3V
-
14%
c)5V
-
14%
d)1V
Explanation
Q.12.
Light of wave length 5000 Angstrom falls on a sensitive plate with photoelectric work function of 1.9 eV. The maximum kinetic energy of the photo electron emitted will be..[ AFMC 1997]
-
27%
a) 1.16 eV
-
9%
b) 2.38 eV
-
36%
c)0.58 eV
-
27%
d)2.98 eV
Explanation
Q.13.
The work function of a metallic substance is 4.0 eV. The longest wavelength of light that can cause photoelectron emission from the substance is approximately.. [ AFMC 1998]
-
25%
a)220 nm
-
42%
b) 310 nm
-
25%
c)400 nm
-
8%
d)540 nm
Explanation
Q.14.
The work function of aluminum is 4.2 eV. If two photons each of energy 3.5 eV strike an electron of aluminum, then emission of electron will be ..[ AFMC 1999]
-
36%
a) depends up on the density of the surface
-
18%
b) data is incomplete
-
27%
c) not possible
-
18%
d) possible
Q.15.
The de-Broglie wave length of an electron of energy 600eV is [ AFMC 2000]
-
20%
a) 4 Angstrom
-
40%
b) 2 Angstrom
-
20%
c) 1 Angstrom
-
20%
d) 0.5 Angstrom
Explanation
Q.16.
The wave length of a particle having a momentum of 2×10-28 kgm/s is ..[ AFMC 2002]
-
25%
a) 3.3×10-6m
-
58%
b) 3.3×105 m
-
8%
c) 3.3×10-4m
-
8%
d) 30 m
Q.17.
What is the de-Broglie wavelength of 1 kg mass moving with a velocity of 10 m/s? [ AFMC 2001]
-
50%
a) 6.626×10-35 m
-
10%
b) 6.626×10-33 m
-
20%
c) 6.626×10-34 m
-
20%
d) none of these
Q.18.
The magnitude of saturation photoelectric current depends upon... [ AFMC 2005]
-
17%
a) frequency
-
42%
b) intensity
-
8%
c) work function
-
33%
d) stopping potential
Q.19.
According to Einstein's photoelectric equation, the plot of kinetic energy of the emitted photoelectrons from a metal vs frequency of the incident radiation gives a straight line whose slope.. [ AFMC 2004]
-
17%
a)depends on the intensity of radiation
-
25%
b) depends on the nature of the metal used
-
33%
c)depends both on the intensity of the radiation and the metal used
-
25%
d)is the same for all metals and independent of the intensity of the radiation
Q.20.
For photoelectric emission, tungsten requires light of 2300Å. If light of 1800Å wave length is incident then emission ...[ AFMC 2005]
-
20%
a) takes place
-
20%
b) doesn't take place
-
20%
c)may or may not take
-
40%
d)depends on frequency
Q.21.
If the minimum energy of photons needed to produce photoelectric effect is 3eV, bombarding the photoelectric material by a number of photons of 2.5eV also one can get...[ AFMC 2006]
-
0%
a) photoelectrons of the same kinetic energy
-
12%
b) photoelectrons of higher kinetic energy
-
75%
c)higher current
-
12%
d)none
Q.22.
What is incorrect about photon? ... [ AFMC 2009]
-
10%
a) Its rest mass is zero
-
30%
b) its energy is hν
-
0%
c) Its momentum is (hν)/c
-
60%
d) It does not exert pressure
Q.23.
The momentum of pfoton of an electromagnetic radiation is 3.3×10-29 kgms-What is the frequaency of the associated waves? [ CBSE-PMT 1990] h=6.6×10-34Js; c=3×108 ms-1
-
50%
a)1.5 × 1013 Hz
-
20%
b) 7.5 × 1012 Hz
-
10%
c)6.0×103
-
20%
d)3.0×103
Q.24.
Number of ejected photoelectron increases with increase ... [ CBSE-PMt 1993]
-
36%
a) in intensity of light
-
9%
b) in wave length of light
-
18%
c)in frequency of light
-
36%
d)never
Q.25.
Which of the following moving particles ( moving with same velocity) has largest wave length of matter waves [ CBSE-PMT 2002]
-
38%
a) Electron
-
25%
b) α-particle
-
38%
c)Proton
-
0%
d)Neutron
Q.26.
Monochromatic light of frequaency 6.0×1014 Hz is produced by a laser. the power emitted is 2×10-3 W. The number of photons emitted, on the average, by the sources per second is ... [ CBSE-PMT 2007]
-
22%
a) 5×1016
-
11%
b) 5×1017
-
44%
c) 5×1014
-
22%
d) 5×1015
Explanation
Q.27.
Which of the following statement is correct? [ CBSE-PME 1997]
-
36%
a) Photo-current increases with intensity of light
-
18%
b) Photo-current is proportional to the applied voltage
-
18%
c)Current in photocell increases with increasing frequency
-
27%
d)Stopping potential increases with increase of incident light
Q.28.
Which of the following statement is correct? [ CBSE-PME 1997]
-
44%
a) Photo-current increases with intensity of light
-
22%
b) Photo-current is proportional to the applied voltage
-
22%
c)Current in photocell increases with increasing frequency
-
11%
d)Stopping potential increases with increase of incident light
Q.29.
The photoelectric work function for a metal surface is 4.125eV. The cut off wavelength for this surface is . [ CBSE-PMT 1999]
-
25%
a) 4125 Å
-
25%
b) 3000 Å
-
25%
c)6000 Å
-
25%
d)2062.5 Å
Q.30.
The momentum of photon of energy 1 MeV in kg m/s, will be [ CBSE-PMT 2006]
-
22%
a) 7×10-24
-
11%
b) 10-22
-
44%
c) 5×10-22
-
22%
d) 0.33×106