Dual Nature of Matter & Radiation Practice Questions - DPP for NEET

 Page 1


DIRECTIONS (Q.1-Q.21) : There are 21 multiple choice
questions. Each question has 4 choices (a), (b), (c) and (d), out
of which ONLY ONE choice is correct.
Q.1 Energy of a a-particle, having de broglie wavelength of
0.004 Å is approximately.
(a) 1275 eV (b) 1200 KeV
(c) 1200 MeV (d) 1200 GeV
Q.2 Velocity of a proton is c/20. Associated de-Broglie
wavelength is (Take h = 6.626 × 10
–34 
J–s)
(a) 2.64 × 10
–24
 mm (b) 2.64 × 10
–24
 cm
(c) 2.64 × 10
–14
 Å (d) 2.64 × 10
–14
 m
Q.3 One electron & one proton is accelerated by equal potential.
Ratio of their de-Broglie wavelengths is-
(a)
p
e
m
m
(b)
e
p
m
m
(c)
p
e
m
m
(d) 1
Q.4 de-Broglie wavelength of an electron is 10 Å then velocity
will be-
(a) 7.2 × 10
7
 m/s (b) 7.2 × 10
6
 m/s
(c) 7.2 × 10
5
 m/s (d) 7.2 × 10
4
 m/s
Q.5 One electron & one proton have equal energies then ratio
of associated de-Broglie wavelength will be-
(a) 1 : (1836)
2
(b)
1836 :1
(c) 1836 : 1 (d) (1836)
2
 : 1
Page 2


DIRECTIONS (Q.1-Q.21) : There are 21 multiple choice
questions. Each question has 4 choices (a), (b), (c) and (d), out
of which ONLY ONE choice is correct.
Q.1 Energy of a a-particle, having de broglie wavelength of
0.004 Å is approximately.
(a) 1275 eV (b) 1200 KeV
(c) 1200 MeV (d) 1200 GeV
Q.2 Velocity of a proton is c/20. Associated de-Broglie
wavelength is (Take h = 6.626 × 10
–34 
J–s)
(a) 2.64 × 10
–24
 mm (b) 2.64 × 10
–24
 cm
(c) 2.64 × 10
–14
 Å (d) 2.64 × 10
–14
 m
Q.3 One electron & one proton is accelerated by equal potential.
Ratio of their de-Broglie wavelengths is-
(a)
p
e
m
m
(b)
e
p
m
m
(c)
p
e
m
m
(d) 1
Q.4 de-Broglie wavelength of an electron is 10 Å then velocity
will be-
(a) 7.2 × 10
7
 m/s (b) 7.2 × 10
6
 m/s
(c) 7.2 × 10
5
 m/s (d) 7.2 × 10
4
 m/s
Q.5 One electron & one proton have equal energies then ratio
of associated de-Broglie wavelength will be-
(a) 1 : (1836)
2
(b)
1836 :1
(c) 1836 : 1 (d) (1836)
2
 : 1
2
DPP/ P 54
Q.6 The ratio of wavelength of deutron & proton accelerated
by an equal potential is
(a)
1
2
(b)
2
1
(c)
1
2
(d)
2
1
Q.7 In photoelectric effect if intensity of light is doubled then
maximum kinetic energy of photoelectrons will become
(a) Double (b) Half
(c) Four time (d) No change
Q.8 Quantum nature of light is explained by which of the
following phenomenon?
(a) Huygen wave theory
(b) Photoelectric effect
(c) Maxwell electromagnetic theory
(d) de- Broglie theory
Q.9 From rest an electron is accelerated between two such
points which has potential 20 & 40 volts respectively.
Associated de-Broglie wavelength of electron is-
(a) 0.75 Å (b) 7.5 Å
(c) 2.75 Å (d) 2.75 m
Q.10An electron microscope uses 40 keV electrons. Find its
resolving limit on the assumption that it is equal to the
wavelength of the electron-
(a) 0.61 Å (b) 0.6 Å
(c) 0.06 Å (d) 0.061 Å
Q.11 A hydrogen atom moving at a speed v absorbs a photon of
wavelength 122 nm and stops. Find the value of v.
(Mass of hydrogen atom = 1.67 × 10
–27
 kg)
(a) 3.5 m/s (b) 32.5 m/s
(c) 3.05 m/s (d) 3.25 m/s
Q.12 The de-Broglie wavelength of an electron is 0.2 Å. Calculate
the potential difference (approximate) required to retard
it to rest-
(a) 3.76 × 10
–3
 V (b) 3.76 × 10
3
 V
(c) 3.76 × 10
3
 eV (d) 376.5 V
Q.13A photon and an electron have equal energy E. l
photon
/
l
electron
 is proportional to
(a) E (b)
1
E
(c)
1
E
(d) Does not depend upon E.
Q.14In a photoemissive cell with exciting wavelength l, the
fastest electron has speed v. If the exciting wavelength is
changed to 3l/4, the speed of the fastest emitted electron
will be
(a) v (3/4)
1/2
(b) v (4/3)
1/2
(c) Less than v (4/3)
1/2
(d) Greater than v (4/3)
1/2
Q.15Which of the following figure repesents variation of
particle momentum and the associated de-Broglie
wavelength?
(a) 
l
p
(b) 
p
l
(c) 
p
l
(d)  
p
l
Q.16 The work function for the surface of aluminium is 4.2 eV .
What will be the  wavelength of that incident light for which
the stopping potential will be zero.
(h » 6.6 × 10
–34
 J–s e » 1.6 × 10
–19
 C)
(a) 2496 Å (b) 2946 × 10
–7
 m
(c) 2649 Å (d) 2946 Å
Page 3


DIRECTIONS (Q.1-Q.21) : There are 21 multiple choice
questions. Each question has 4 choices (a), (b), (c) and (d), out
of which ONLY ONE choice is correct.
Q.1 Energy of a a-particle, having de broglie wavelength of
0.004 Å is approximately.
(a) 1275 eV (b) 1200 KeV
(c) 1200 MeV (d) 1200 GeV
Q.2 Velocity of a proton is c/20. Associated de-Broglie
wavelength is (Take h = 6.626 × 10
–34 
J–s)
(a) 2.64 × 10
–24
 mm (b) 2.64 × 10
–24
 cm
(c) 2.64 × 10
–14
 Å (d) 2.64 × 10
–14
 m
Q.3 One electron & one proton is accelerated by equal potential.
Ratio of their de-Broglie wavelengths is-
(a)
p
e
m
m
(b)
e
p
m
m
(c)
p
e
m
m
(d) 1
Q.4 de-Broglie wavelength of an electron is 10 Å then velocity
will be-
(a) 7.2 × 10
7
 m/s (b) 7.2 × 10
6
 m/s
(c) 7.2 × 10
5
 m/s (d) 7.2 × 10
4
 m/s
Q.5 One electron & one proton have equal energies then ratio
of associated de-Broglie wavelength will be-
(a) 1 : (1836)
2
(b)
1836 :1
(c) 1836 : 1 (d) (1836)
2
 : 1
2
DPP/ P 54
Q.6 The ratio of wavelength of deutron & proton accelerated
by an equal potential is
(a)
1
2
(b)
2
1
(c)
1
2
(d)
2
1
Q.7 In photoelectric effect if intensity of light is doubled then
maximum kinetic energy of photoelectrons will become
(a) Double (b) Half
(c) Four time (d) No change
Q.8 Quantum nature of light is explained by which of the
following phenomenon?
(a) Huygen wave theory
(b) Photoelectric effect
(c) Maxwell electromagnetic theory
(d) de- Broglie theory
Q.9 From rest an electron is accelerated between two such
points which has potential 20 & 40 volts respectively.
Associated de-Broglie wavelength of electron is-
(a) 0.75 Å (b) 7.5 Å
(c) 2.75 Å (d) 2.75 m
Q.10An electron microscope uses 40 keV electrons. Find its
resolving limit on the assumption that it is equal to the
wavelength of the electron-
(a) 0.61 Å (b) 0.6 Å
(c) 0.06 Å (d) 0.061 Å
Q.11 A hydrogen atom moving at a speed v absorbs a photon of
wavelength 122 nm and stops. Find the value of v.
(Mass of hydrogen atom = 1.67 × 10
–27
 kg)
(a) 3.5 m/s (b) 32.5 m/s
(c) 3.05 m/s (d) 3.25 m/s
Q.12 The de-Broglie wavelength of an electron is 0.2 Å. Calculate
the potential difference (approximate) required to retard
it to rest-
(a) 3.76 × 10
–3
 V (b) 3.76 × 10
3
 V
(c) 3.76 × 10
3
 eV (d) 376.5 V
Q.13A photon and an electron have equal energy E. l
photon
/
l
electron
 is proportional to
(a) E (b)
1
E
(c)
1
E
(d) Does not depend upon E.
Q.14In a photoemissive cell with exciting wavelength l, the
fastest electron has speed v. If the exciting wavelength is
changed to 3l/4, the speed of the fastest emitted electron
will be
(a) v (3/4)
1/2
(b) v (4/3)
1/2
(c) Less than v (4/3)
1/2
(d) Greater than v (4/3)
1/2
Q.15Which of the following figure repesents variation of
particle momentum and the associated de-Broglie
wavelength?
(a) 
l
p
(b) 
p
l
(c) 
p
l
(d)  
p
l
Q.16 The work function for the surface of aluminium is 4.2 eV .
What will be the  wavelength of that incident light for which
the stopping potential will be zero.
(h » 6.6 × 10
–34
 J–s e » 1.6 × 10
–19
 C)
(a) 2496 Å (b) 2946 × 10
–7
 m
(c) 2649 Å (d) 2946 Å
DPP/ P 54
3
Q.17 Slope of V
0
 – n curve is-
(where V
0
 =  Stopping potential and n = frequency)
(a)e (b)
h
e
(c) f
0
(d)h
Q.18 A radio station is transmitting waves of wavelength 300 m.
If diffracting power of transmitter is 10 kW , then numbers
of photons diffracted per second is-
(a) 1.5 × 10
35
(b) 1.5 × 10
31
(c) 1.5 × 10
29
(d) 1.5 × 10
33
Q.19Light of wavelength 3320 Å is incident on metal surface
(work function = 1.07 eV). To stop emission of photo
electron,  retarding potential required to be
(Take hc » 12420 eV – Å)
(a) 3.74 V (b) 2.67 V (c) 1.07 V (d) 4.81 V
Q.20 The figure shows the variation of photocurrent with anode
potential for a photo-sensitive surface for three different
radiations. Let I
a
, I
b
 and I
c
 be the intensities and f
a
, f
b
 and f
c
be the frequencies for the curves a, b and c respectively.
Then
(a) f
a
 = f
b
 and I
a
 ¹ I
b
(b) f
a
 = f
c
 and I
a
 = I
c
(c) f
a
 = f
b
 and I
a
 = I
b
O
c
b
a
(d) f
a
 = f
b
 and I
a
 = I
c
Q.21 An electromagnetic radiation of frequency 3 × 10
15
 cycles
per second falls on a photo electric surface whose work
function is 4.0 eV. Find out the maximum velocity of the
photo electrons emitted by the surface-
(a) 13.4 × 10
–19
 m/s (b) 19.8 × 10
–19
m/s
(c) 1.73 × 10
6
 m/s (d) None
DIRECTIONS (Q.22-Q.24) : In the following questions,
more than one of the answers  given are correct. Select
the correct answers and mark it according to the following
codes:
Codes :
(a) 1, 2 and 3 are correct (b) 1 and 2 are correct
(c) 2 and 4 are correct (d) 1 and 3 are correct
Q.22Ultraviolet light of wavelength 280 nm is used in an
experiment on photo electric effect with lithium (f = 2.5
eV) cathode.
(1) The maximum kinetic energy is 1 .9 eV
(2) The stopping potential is1.9 V
(3) The maximum kinetic energy is 4.4 V
(4) The stopping potential is 4.4 eV
Q.23The separation between Bragg’s planes in a crystal is
10 Å. Then the wavelength of those X-rays which can be
diffracted by this crystal is-
(1) 5 Å (2) 10 Å
(3) 20 Å (4) 25 Å
Q.24Electrons are accelerated in television tubes through
potential difference of about 10 KV.
(1) The lowest wavelength of the emitted X-rays is 12.4Å
(2) The lowest wavelength of the emitted X-rays is 1.24Å
(3) The highest frequency of the emitted X-rays is
2.4 × 10
8
 Hz
(4) The highest frequency of the emitted X-rays is
2.4 × 10
18
 Hz
DIRECTIONS (Q.25-Q.27) : Read the passage given below
and answer the questions that follows :
A physicist wishes to eject electrons by shining light on a metal
surface. The light source emits light of wavelength of 450 nm.
The table lists the only available metals and their work functions.
Metal W
0
 (eV)
Barium 2.5
Lithium 2.3
Tantalum 4.2
Tungsten 4.5
Q.25Which metal(s) can be used to produce electrons by the
photoelectric effect from given source of light ?
(a) Barium only
(b) Barium or lithium
(c) Lithium, tantalum or tungsten
(d) Tungsten or tantalum
Page 4


DIRECTIONS (Q.1-Q.21) : There are 21 multiple choice
questions. Each question has 4 choices (a), (b), (c) and (d), out
of which ONLY ONE choice is correct.
Q.1 Energy of a a-particle, having de broglie wavelength of
0.004 Å is approximately.
(a) 1275 eV (b) 1200 KeV
(c) 1200 MeV (d) 1200 GeV
Q.2 Velocity of a proton is c/20. Associated de-Broglie
wavelength is (Take h = 6.626 × 10
–34 
J–s)
(a) 2.64 × 10
–24
 mm (b) 2.64 × 10
–24
 cm
(c) 2.64 × 10
–14
 Å (d) 2.64 × 10
–14
 m
Q.3 One electron & one proton is accelerated by equal potential.
Ratio of their de-Broglie wavelengths is-
(a)
p
e
m
m
(b)
e
p
m
m
(c)
p
e
m
m
(d) 1
Q.4 de-Broglie wavelength of an electron is 10 Å then velocity
will be-
(a) 7.2 × 10
7
 m/s (b) 7.2 × 10
6
 m/s
(c) 7.2 × 10
5
 m/s (d) 7.2 × 10
4
 m/s
Q.5 One electron & one proton have equal energies then ratio
of associated de-Broglie wavelength will be-
(a) 1 : (1836)
2
(b)
1836 :1
(c) 1836 : 1 (d) (1836)
2
 : 1
2
DPP/ P 54
Q.6 The ratio of wavelength of deutron & proton accelerated
by an equal potential is
(a)
1
2
(b)
2
1
(c)
1
2
(d)
2
1
Q.7 In photoelectric effect if intensity of light is doubled then
maximum kinetic energy of photoelectrons will become
(a) Double (b) Half
(c) Four time (d) No change
Q.8 Quantum nature of light is explained by which of the
following phenomenon?
(a) Huygen wave theory
(b) Photoelectric effect
(c) Maxwell electromagnetic theory
(d) de- Broglie theory
Q.9 From rest an electron is accelerated between two such
points which has potential 20 & 40 volts respectively.
Associated de-Broglie wavelength of electron is-
(a) 0.75 Å (b) 7.5 Å
(c) 2.75 Å (d) 2.75 m
Q.10An electron microscope uses 40 keV electrons. Find its
resolving limit on the assumption that it is equal to the
wavelength of the electron-
(a) 0.61 Å (b) 0.6 Å
(c) 0.06 Å (d) 0.061 Å
Q.11 A hydrogen atom moving at a speed v absorbs a photon of
wavelength 122 nm and stops. Find the value of v.
(Mass of hydrogen atom = 1.67 × 10
–27
 kg)
(a) 3.5 m/s (b) 32.5 m/s
(c) 3.05 m/s (d) 3.25 m/s
Q.12 The de-Broglie wavelength of an electron is 0.2 Å. Calculate
the potential difference (approximate) required to retard
it to rest-
(a) 3.76 × 10
–3
 V (b) 3.76 × 10
3
 V
(c) 3.76 × 10
3
 eV (d) 376.5 V
Q.13A photon and an electron have equal energy E. l
photon
/
l
electron
 is proportional to
(a) E (b)
1
E
(c)
1
E
(d) Does not depend upon E.
Q.14In a photoemissive cell with exciting wavelength l, the
fastest electron has speed v. If the exciting wavelength is
changed to 3l/4, the speed of the fastest emitted electron
will be
(a) v (3/4)
1/2
(b) v (4/3)
1/2
(c) Less than v (4/3)
1/2
(d) Greater than v (4/3)
1/2
Q.15Which of the following figure repesents variation of
particle momentum and the associated de-Broglie
wavelength?
(a) 
l
p
(b) 
p
l
(c) 
p
l
(d)  
p
l
Q.16 The work function for the surface of aluminium is 4.2 eV .
What will be the  wavelength of that incident light for which
the stopping potential will be zero.
(h » 6.6 × 10
–34
 J–s e » 1.6 × 10
–19
 C)
(a) 2496 Å (b) 2946 × 10
–7
 m
(c) 2649 Å (d) 2946 Å
DPP/ P 54
3
Q.17 Slope of V
0
 – n curve is-
(where V
0
 =  Stopping potential and n = frequency)
(a)e (b)
h
e
(c) f
0
(d)h
Q.18 A radio station is transmitting waves of wavelength 300 m.
If diffracting power of transmitter is 10 kW , then numbers
of photons diffracted per second is-
(a) 1.5 × 10
35
(b) 1.5 × 10
31
(c) 1.5 × 10
29
(d) 1.5 × 10
33
Q.19Light of wavelength 3320 Å is incident on metal surface
(work function = 1.07 eV). To stop emission of photo
electron,  retarding potential required to be
(Take hc » 12420 eV – Å)
(a) 3.74 V (b) 2.67 V (c) 1.07 V (d) 4.81 V
Q.20 The figure shows the variation of photocurrent with anode
potential for a photo-sensitive surface for three different
radiations. Let I
a
, I
b
 and I
c
 be the intensities and f
a
, f
b
 and f
c
be the frequencies for the curves a, b and c respectively.
Then
(a) f
a
 = f
b
 and I
a
 ¹ I
b
(b) f
a
 = f
c
 and I
a
 = I
c
(c) f
a
 = f
b
 and I
a
 = I
b
O
c
b
a
(d) f
a
 = f
b
 and I
a
 = I
c
Q.21 An electromagnetic radiation of frequency 3 × 10
15
 cycles
per second falls on a photo electric surface whose work
function is 4.0 eV. Find out the maximum velocity of the
photo electrons emitted by the surface-
(a) 13.4 × 10
–19
 m/s (b) 19.8 × 10
–19
m/s
(c) 1.73 × 10
6
 m/s (d) None
DIRECTIONS (Q.22-Q.24) : In the following questions,
more than one of the answers  given are correct. Select
the correct answers and mark it according to the following
codes:
Codes :
(a) 1, 2 and 3 are correct (b) 1 and 2 are correct
(c) 2 and 4 are correct (d) 1 and 3 are correct
Q.22Ultraviolet light of wavelength 280 nm is used in an
experiment on photo electric effect with lithium (f = 2.5
eV) cathode.
(1) The maximum kinetic energy is 1 .9 eV
(2) The stopping potential is1.9 V
(3) The maximum kinetic energy is 4.4 V
(4) The stopping potential is 4.4 eV
Q.23The separation between Bragg’s planes in a crystal is
10 Å. Then the wavelength of those X-rays which can be
diffracted by this crystal is-
(1) 5 Å (2) 10 Å
(3) 20 Å (4) 25 Å
Q.24Electrons are accelerated in television tubes through
potential difference of about 10 KV.
(1) The lowest wavelength of the emitted X-rays is 12.4Å
(2) The lowest wavelength of the emitted X-rays is 1.24Å
(3) The highest frequency of the emitted X-rays is
2.4 × 10
8
 Hz
(4) The highest frequency of the emitted X-rays is
2.4 × 10
18
 Hz
DIRECTIONS (Q.25-Q.27) : Read the passage given below
and answer the questions that follows :
A physicist wishes to eject electrons by shining light on a metal
surface. The light source emits light of wavelength of 450 nm.
The table lists the only available metals and their work functions.
Metal W
0
 (eV)
Barium 2.5
Lithium 2.3
Tantalum 4.2
Tungsten 4.5
Q.25Which metal(s) can be used to produce electrons by the
photoelectric effect from given source of light ?
(a) Barium only
(b) Barium or lithium
(c) Lithium, tantalum or tungsten
(d) Tungsten or tantalum
4
DPP/ P 54
Q.26Which option correctly identifies the metal that will
produce the most energetic electrons and their energies ?
(a) Lithium, 0.45 eV (b) Tungsten, 1.75 eV
(c) Lithium, 2.30 eV (d) Tungsten, 2.75 eV
Q.27 Suppose photoelectric experiment is done separately with
these metals with light of wavelength 450 nm. The
maximum magnitude of stopping potential amongst all the
metals is-
(a) 2.75 volt (b) 4.5 volt
(c) 0.45 volt (d) 0.25 volt
DIRECTIONS (Q. 28-Q.30) : Each of these questions contains
two statements: Statement-1 (Assertion) and Statement-2
(Reason). Each of these questions has four alternative choices,
only one of which is the correct answer. You have to select
the correct choice.
(a) Statement-1 is True, Statement-2 is True; Statement-2 is a
correct explanation for  Statement-1.
(b) Statement-1 is True, Statement-2 is True; Statement-2 is
NOT a correct explanation for Statement-1.
(c) Statement -1 is False, Statement-2 is True.
(d) Statement -1 is True, Statement-2 is False.
Q.28 Statement -1 : Mass of moving photon varies directly as
the wavelength.
Statement -2 : Energy of the particle = Mass × (Speed of
light)
2
Q.29 Statement -1 : Photosensitivity of a metal is large if its
work function is small.
Statement -2 : Work function = hf
0
 where f
0
 is the
threshold frequency.
Q.30 Statement -1 : The de-Broglie wavelength of a molecule
varies inversely as the square root of temperature.
Statement -2 : The root mean square velocity of the
molecule is proportional to square root of absolute
temperature.