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Dual nature of matter

Total questions: 25

Worksheet time: 26mins

Name
Class
Date
1.

The only way to increase the number of photoelectrons emitted is by increasing the _________ of the light

a)

Intensity

b)

Wavelength

c)

Frequency

d)

Energy

2.

A particle of light is called a...

a)

Photoelectron

b)

Photon

c)

Proton

d)

Electron

3.

What color of light has the greatest energy per photon?

a)

Red

b)

Green

c)

Blue

d)

Violet

4.
This image is an illustration of
a)
photoelectric effect
b)
Dalton's atomic theory
c)
Bohr model
d)
Quantum mechanical model
5.
The photoelectric effect only occurs if the light shining on the metal is:
a)
coherent.
b)
above a minimum intensity.
c)
above a minimum frequency.
d)
above a minimum wavelength.
6.
Which statement about the photoelectric effect is correct?
a)
Electrons are emitted instantaneously.
b)
Electrons are not emitted below a certain wavelength.
c)
You can change the energy of the electrons by changing the intensity.
d)
Electron energy is independent of frequency.
7.
The cut-off wavelength for the photoelectric effect of platinum is 220 nm. Find the work function of platinum in eV
a)
11.25 eV
b)
9 eV
c)
4.5 eV
d)
5.65 eV
8.

In photoelectric effect, electrons should be removed from the

a)

inner shells

b)

surface

c)

from core

d)

nucleus

9.

What is the energy of a photon with a frequency of 5x1014 Hz? (you need to do calculation. You have enough time)

a)

2.5x10-19 J

b)

3.0x10-19 J

c)

3.3x10-19 J

d)

4.5x10-19 J

10.

What is the best description of 'threshold frequency'?

a)

The minimum energy needed for electrons to escape a surface.

b)

The maximum kinetic energy that an emitted electron has.

c)

The minimum frequency of a photon that will cause an electron to be emitted.

d)

The frequency that an emitted electron will have.

11.

According to the de Broglie hypothesis, which of the following statements is applicable to the

wavelength of a moving particle?

a)

directly proportional to its energy

b)

directly proportional to its momentum

c)

inversely proportional to its energy

d)

inversely proportional to its momentum

12.

According to de Broglie, as the momentum of a moving particle is tripled, the corresponding

wavelength changes by what factor?

a)

1/9

b)

1/3

c)

3

d)

9

13.

Starting from rest, an electron accelerates through a potential difference of 40 V. What is its de Broglie

wavelength? (h = 6.63*10-34 J×s, me = 9.11*10-31kg, and 1 eV = 1.60 * 10-19J)

a)

1.1*10-10 m

b)

1.5*10-10 m

c)

1.9 * 10-10 m

d)

2.3*10-10 m

14.

If an electron has a measured wavelength of 0.850 * 10-10m, what is its kinetic energy?

(h= 6.63 *10-34 J×s, 1 eV = 1.6 *10-19J, and me = 9.11 * 10-31 kg

a)

55.0 eV

b)

104 eV

c)

147 eV

d)

209 eV

15.

An electron microscope operates with electrons of kinetic energy 50.0 keV. What is the wavelength of

these electrons? Assume this speed is not relativistic.

a)

9.28* 10-10 m

b.

b)

7.14*10-11 m

c)

5.49´ 10-12 m

d)

2.75* 10-13 m

16.

That light has a dual nature is referring to light:

a)

having high- or low-energy photons.

b)

acting as waves and particles.

c)

having energy and momentum

d)

undergoing pair production.

17.

· All moving particles have a "matter wave" with a wavelength associated with them" This hypothesis has a name. Which?

a)

Davisson and Germer hypothesis

b)

De Broglie hypothesis

c)

Schrödinger hypothesis

d)

Bainbridge hypothesis

18.

The relation between photocurrent and intensity of light is:

a)
b)
c)
d)

NONE

19.

In nuclear reactors, neutrons travel with

energies of 5 × 10-21 J. Find their wavelength in A0

a)

1.62

b)

16.2

c)

0.162

d)

162

20.

de-Broglie associated with an electron accelerated through a potential difference V is λ. What will be its wavelength when the accelerating potential is increased to 4V?

a)

λ

b)

λ/2

c)

d)

12.27 λ

21.

electron volt is a unit of

a)

potential

b)

momentum

c)

energy

d)

charge

22.

The theory, on the basis of Photoelectric effect can be explained

a)

corpuscular theory

b)

electromagnetic theory

c)

wave theory

d)

quantum theory

23.

Which experimental setup helped De broglie to prove the hypothesis?

a)

Bose-Einstein experiment

b)

Davisson–Germer experiment

c)

Plank-Maxwell experiment

d)

Bohr-Rutherford experiment

24.

Observation : Bright blue light liberates photoelectrons from

the surface of lithium but red light from the

same intensity does not give off any electrons

at all.

Explanation : Photons of blue light carry more energy than

photons of red light because the frequency of

blue light is higher than the frequency of red

light

DOES THE EXPLANATION EXPLAIN THE OBSERVATION?

a)

YES

b)

NO

25.

Observation : Bright blue light liberates photoelectrons from

the surface of lithium but red light from the

same intensity does not give off any electrons

at all.

Explanation : The intensity of red light is not sufficient to

liberate photoelectrons

DOES THE EXPLANATION EXPLAIN THE OBSERVATION?

a)

YES

b)

NO