Dual Nature of Radiation and Matter Test 6

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Dual Nature of Radiation and Matter Test 6

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Question 1
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Directions : In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as.
Assertion (A): Photoelectric effect demonstrates the particle nature of light.
Reason (R): The number of photoelectrons is proportional to the frequency of light.

A
A. Both A and R are true and R is the correct explanation of A

B
B. Both A and R are true but R is NOT the correct explanation of A

C
C. A is true but R is false

D
D. A is false and R is true

Solution

Photoelectric effect demonstrates the particle nature of light. So the assertion is true.
Number of emitted photoelectrons depends upon the intensity of light. So the reason is false.
Question 2
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Directions : In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as.
Assertion (A): Photosensitivity of a material is high if its work function is low.
Reason (R): Work function = hf₀, where f₀ is threshold frequency.

A
A. Both A and R are true and R is the correct explanation of A

B
B. Both A and R are true but R is NOT the correct explanation of A

C
C. A is true but R is false

D
D. A is false and R is true

Solution

Work function is less means less energy is required to eject photoelectrons. So, if the work function is less photosensitivity is high. So the assertion is true.
Work function is the minimum energy required to eject a photoelectron and Work function = hf₀, where f₀ is threshold frequency. So reason is also true but it does not explain the assertion.
Question 3
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Directions : In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as.
Assertion (A): de-Broglie wavelength of a gas molecule is inversely proportional to the square root of temperature.
Reason (R): The root mean square velocity of gas molecules depends on temperature.

A
A. Both A and R are true and R is the correct explanation of A

B
B. Both A and R are true but R is NOT the correct explanation of A

C
C. A is true but R is false

D
D. A is false and R is true

Solution

So, v_RMS ∝ √T Again de-Broglie wavelength, λ = h/mv
So, λ ∝ 1/√T
Hence, assertion and reason both are true and reason explains the assertion.
Question 4
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Directions : In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as.
Assertion (A): The energy (E) and momentum (p) of a photon are related as p = E/c
Reason (R): The photon behaves like a particle.

A
A. Both A and R are true and R is the correct explanation of A

B
B. Both A and R are true but R is NOT the correct explanation of A

C
C. A is true but R is false

D
D. A is false and R is true

Solution

Energy= E = hc/λ
Momentum = P = h/λ.
So, P = E/c
This is true only when photon has a particle nature.
So, assertion and reason both are true and reason properly explains the assertion.
Question 5
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Directions : In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as.
Assertion (A): Kinetic energy of photoelectrons emitted by a photosensitive surface depends upon the frequency of incident photon.
Reason (R): The ejection of electrons from metallic surface is possible with frequency of incident photon below the threshold frequency.

A
A. Both A and R are true and R is the correct explanation of A

B
B. Both A and R are true but R is NOT the correct explanation of A

C
C. A is true but R is false

D
D. A is false and R is true

Solution

K.E. depends upon the frequency. So assertion is true.
Photoelectron emitted when frequency of incident radiation is more than the threshold frequency. So reason is also false.
Question 6
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Directions : In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as.
Assertion (A): de-Broglie equation is significant for microscopic particles.
Reason (R): de-Broglie wavelength is inversely proportional to the mass of a particle when velocity is kept constant.

A
A. Both A and R are true and R is the correct explanation of A

B
B. Both A and R are true but R is NOT the correct explanation of A

C
C. A is true but R is false

D
D. A is false and R is true

Solution

de-Broglie wavelength, λ = h/mv h and v remaining constant, λ ∝ 1/m So, as the mass of the particle becomes smaller and smaller the de-Broglie wavelength of the particle becomes more and more significant.
Hence, assertion and reason both are true and reason explains the assertion properly.
Question 7
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Directions : In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as.
Assertion (A): Resolving power of electron microscope increases as electron is accelerated through higher voltage.
Reason (R): de-Broglie wavelength of electron decreases as accelerating voltage of electron increases.

A
A. Both A and R are true and R is the correct explanation of A

B
B. Both A and R are true but R is NOT the correct explanation of A

C
C. A is true but R is false

D
D. A is false and R is true

Solution

de-Broglie wavelength is given by λ =
So, as accelerating potential (V) increases, the wavelength decreases.
Resolving power of microscope =
So, as wavelength (λ) decreases, resolving power increases.
So, assertion and reason both are true and reason explains the assertion.
Question 8
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Directions: These questions consist of two statements, each printed as Assertion and Reason. While answering these questions, you are required to choose any one of the following four responses.
Assertion : Though light of a single frequency (monochromatic) is incident on a metal, the energies of emitted photoelectrons are different.
Reason : The energy of electrons emitted from inside the metal surface is lost in collision with the other atoms in the metal.

A
A. If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion.

B
B. If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.

C
C. If the Assertion is correct but Reason is incorrect.

D
D. If both the Assertion and Reason are incorrect.

Solution

When a light of single frequency falls on the electrons of inner layer of metal, then this electron comes out of the metal surface after a large number of collisions with atom of it’s upper layer.
Question 9
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Directions: These questions consist of two statements, each printed as Assertion and Reason. While answering these questions, you are required to choose any one of the following four responses.
Assertion : Photoelectric saturation current increases with the increase in frequency of incident light.
Reason : Energy of incident photons increases with increase in frequency and as a result photoelectric current increases.

A
A. If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion.

B
B. If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.

C
C. If the Assertion is correct but Reason is incorrect.

D
D. If both the Assertion and Reason are incorrect.

Solution

Photoelectric saturation current is independent of frequency. It only depends on the intensity of light.
Question 10
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Directions: These questions consist of two statements, each printed as Assertion and Reason. While answering these questions, you are required to choose any one of the following four responses.
Assertion : The photon behaves like a particle.
Reason : If E and P are the energy and momentum of the photon, then p = E / c .

A
A. If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion.

B
B. If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.

C
C. If the Assertion is correct but Reason is incorrect.

D
D. If both the Assertion and Reason are incorrect.

Solution

Momentum of a platform is given by
p = hλ (by de Broglie hypothesis)... (i)
Also the photon is a form of energy packet behave as a particle and having energy
E = hcλ...(ii)
From (i) and (ii), p = E/c or, hv/c.
Question 11
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Directions: These questions consist of two statements, each printed as Assertion and Reason. While answering these questions, you are required to choose any one of the following four responses.
Assertion : Two photons of equal wavelength must have equal linear momentum.
Reason : Two photons of equal linear momentum will have equal wavelength.

A
A. If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion.

B
B. If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.

C
C. If the Assertion is correct but Reason is incorrect.

D
D. If both the Assertion and Reason are incorrect.

Solution

To photons of equal wavelength will have equal momentum (magnitude), but direction of momentum may be different.
Question 12
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Directions: These questions consist of two statements, each printed as Assertion and Reason. While answering these questions, you are required to choose any one of the following four responses.
Assertion : In the process of photoelectric emission, all emitted electrons do not have the same kinetic energy.
Reason : If radiation falling on a photosensitive surface of a metal consists of different wavelengths then energy acquired by electrons absorbing photons of different wavelengths shall be different.

A
A. If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion.

B
B. If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.

C
C. If the Assertion is correct but Reason is incorrect.

D
D. If both the Assertion and Reason are incorrect.

Solution

Both statement I and II are true; but even it radiation of single wavelength is incident on photosensitive surface, electrons of different KE will be emitted.
Question 13
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Directions: These questions consist of two statements, each printed as Assertion and Reason. While answering these questions, you are required to choose any one of the following four responses.
Assertion : The photoelectrons produced by a monochromatic light beam incident on a metal surface have a spread in their kinetic energies.
Reason : The work function of the metal is its characteristic property.

A
A. If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion.

B
B. If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.

C
C. If the Assertion is correct but Reason is incorrect.

D
D. If both the Assertion and Reason are incorrect.

Solution

The kinetic energy of emitted photoelectrons varies from zero to a maximum value. Work function depends on metal used.
Question 14
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Directions: These questions consist of two statements, each printed as Assertion and Reason. While answering these questions, you are required to choose any one of the following four responses.
Assertion : Photosensitivity of a metal is high if its work function is small.
Reason : Work function = hf0 where f0 is the threshold frequency.

A
A. If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion.

B
B. If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.

C
C. If the Assertion is correct but Reason is incorrect.

D
D. If both the Assertion and Reason are incorrect.

Solution

Less work function means less energy is required for ejecting out the electrons.
Question 15
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Directions: These questions consist of two statements, each printed as Assertion and Reason. While answering these questions, you are required to choose any one of the following four responses.
Assertion : In an experiment on photoelectric effect, a photon is incident on an electron from one direction and the photoelectron is emitted almost in the opposite direction. It violates the principle of conservation of linear momentum.
Reason : It does not violate the principle of conservation of linear momentum.

A
A. If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion.

B
B. If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.

C
C. If the Assertion is correct but Reason is incorrect.

D
D. If both the Assertion and Reason are incorrect.

Solution

The photoelectron is emitted in the opposite direction to that of the direction of the incident photon, and does not violate the conservation of momentum. The conservation of momentum is based on Newton's third law which says that the forces acting during collision are equal and opposite. Thus, during collision of photon and electron, the photoelectron is emitted in the opposite direction.
Question 16
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Directions: These questions consist of two statements, each printed as Assertion and Reason. While answering these questions, you are required to choose any one of the following four responses.
Assertion : Two sources of equal intensity always emit equal number of photons in any time interval.
Reason : Two sources of equal intensity may emit equal number of photons in any time interval.

A
A. If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion.

B
B. If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.

C
C. If the Assertion is correct but Reason is incorrect.

D
D. If both the Assertion and Reason are incorrect.

Solution

Total number of emitted photons depends on energy of each photon. The energy of photons of two sources may be different.
Question 17
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Directions: These questions consist of two statements, each printed as Assertion and Reason. While answering these questions, you are required to choose any one of the following four responses.
Assertion : The kinetic energy of photoelectrons emitted from metal surface does not depend on the intensity of incident photon.
Reason : The ejection of electrons from metallic surface is not possible with frequency of incident photons below the threshold frequency.

A
A. If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion.

B
B. If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.

C
C. If the Assertion is correct but Reason is incorrect.

D
D. If both the Assertion and Reason are incorrect.

Solution

Intensity of incident photon decides the number of electrons ejected and not the kinetic energy.
Ejection of electrons from metallic surfaces is possible only when the frequency of incident photon is more than threshold frequency.

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Dual Nature of Radiation and Matter Test 6

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Question 1

A. Both A and R are true and R is the correct explanation of A

B. Both A and R are true but R is NOT the correct explanation of A

C. A is true but R is false

D. A is false and R is true

Solution

Question 2

A. Both A and R are true and R is the correct explanation of A

B. Both A and R are true but R is NOT the correct explanation of A

C. A is true but R is false

D. A is false and R is true

Solution

Question 3

A. Both A and R are true and R is the correct explanation of A

B. Both A and R are true but R is NOT the correct explanation of A

C. A is true but R is false

D. A is false and R is true

Solution

Question 4

A. Both A and R are true and R is the correct explanation of A

B. Both A and R are true but R is NOT the correct explanation of A

C. A is true but R is false

D. A is false and R is true

Solution

Question 5

A. Both A and R are true and R is the correct explanation of A

B. Both A and R are true but R is NOT the correct explanation of A

C. A is true but R is false

D. A is false and R is true

Solution

Question 6

A. Both A and R are true and R is the correct explanation of A

B. Both A and R are true but R is NOT the correct explanation of A

C. A is true but R is false

D. A is false and R is true

Solution

Question 7

A. Both A and R are true and R is the correct explanation of A

B. Both A and R are true but R is NOT the correct explanation of A

C. A is true but R is false

D. A is false and R is true

Solution

Question 8

A. If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion.

B. If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.

C. If the Assertion is correct but Reason is incorrect.

D. If both the Assertion and Reason are incorrect.

Solution

Question 9

A. If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion.

B. If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.

C. If the Assertion is correct but Reason is incorrect.

D. If both the Assertion and Reason are incorrect.

Solution

Question 10

A. If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion.

B. If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.

C. If the Assertion is correct but Reason is incorrect.

D. If both the Assertion and Reason are incorrect.

Solution

Question 11

A. If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion.

B. If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.

C. If the Assertion is correct but Reason is incorrect.

D. If both the Assertion and Reason are incorrect.

Solution

Question 12

A. If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion.

B. If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.

C. If the Assertion is correct but Reason is incorrect.

D. If both the Assertion and Reason are incorrect.

Solution