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Diffraction and Interference

Total questions: 30

Worksheet time: 24mins

Name
Class
Date
1.

What type of interference is represented in this diagram?

a)

Constructive

b)

Destructive

2.

What type of interference is represented in the diagram?

a)

Constructive

b)

Destructive

3.

What's happening at A?

a)

Two crests are combining to create constructive interference.

b)

A crest and a trough are combining to create destructive interference.

c)

Two crests are combining to create destructive interference.

d)

A crest and trough are combining to create constructive interference.

4.

What is happening at B?

a)

Two crests are combining to create constructive interference.

b)

A crest and a trough are combining to create destructive interference.

c)

Two crests are combining to create destructive interference.

d)

A crest and a trough are combining to create constructive interference.

5.
Two longitudinal waves overlap.  Compressions overlap with compressions.  Rarefactions overlap with rarefactions.  The waves are
a)
In-phase
b)
Out-of-phase
c)
In-synchronicity
d)
Out-of-synchronicity
6.

Interference effects observed in the early 1800s

were instrumental in supporting a concept of the

existence of which property of light?

a)

Polarization

b)

Particle nature

c)

Wave nature

d)

Electromagnetic character

7.

The term coherence relates to ______.

a)

the phase relationship between two waves

b)

the polarization state of two waves

c)

the diffraction of two waves

d)

the amplitude of two waves

8.

Which of the following figures represent is a double

slit interference pattern?

a)

A

b)

B

c)

C

d)

D

9.

What does one observe on the screen in a Young's experiment if white light illuminates the double slit instead of light of a single wavelength?

a)

A white central fringe and no other fringes

b)

A dark central fringe and a series of alternating white and dark fringes on each side of the center

c)

A white central fringe and a series of colored and dark fringes on each side of the center

d)

A continuous band of colors with no dark fringes anywhere

10.

In a Young's double slit experiment, green light is

incident on the two slits. The interference pattern is

observed on a screen. Which one of the following

changes would cause the fringes to be more closely

spaced?

a)

Reduce the slit separation distance

b)

Use red light instead of green light

c)

Use blue light instead of green light

d)

Move the screen farther away from the slits

11.

Monochromatic coherent light shines through a

pair of slits. If the distance between these slits is

decreased, which of the following statements is/are

true of the resulting interference pattern?

I. The distance between the maxima stays the

same

II. The distance between the maxima decreases

III. The distance between the minima increases

IV. The distance between the maxima increases

a)

I only

b)

I and III only

c)

II and III only

d)

III and IV only

12.

Monochromatic coherent light shines through a

pair of slits. If the wavelength of the light is

decreased, which of the following statements is/are

true of the resulting interference pattern?

I. The distance between the maxima stays the

same

II. The distance between the maxima decreases

III. The distance between the minima stays the

same

IV. The distance between the minima decreases.

a)

I and III only

b)

I and IV only

c)

II and III only

d)

II and IV only

13.

In a double-slit interference experiment you are

asked to use laser light of different wavelengths and

determine the separation between adjacent maxima.

You observe that this separation is greatest when you

illuminate the double slit with _____.

a)

blue light

b)

green light

c)

yellow light

d)

red light

14.

What do we mean when we say that two light

rays striking a screen are in phase with each other?

a)

When the electric field due to one is a maximum, the electric field due to the other is also a maximum, and this relation is maintained as time passes

b)

They are traveling at the same speed

c)

They have the same wavelength

d)

They alternately reinforce and cancel each other

15.

Two light sources are said to be coherent if they are ______.

a)

of the same frequency

b)

of the same frequency, and maintain a constant phase difference

c)

of the same amplitude, and maintain a constant phase difference

d)

of the same frequency and amplitude

16.

Two beams of coherent light start out at the same

point in phase and travel different paths to arrive at

point 𝑃. If the maximum constructive interference is

to occur at point 𝑃, the two beams must travel paths

that differ by _______.

a)

a whole number of wavelengths

b)

a whole number of half-wavelengths

c)

an odd number of wavelengths

d)

an odd number of half-wavelengths

17.

Two beams of coherent light start out at the same

point in phase and travel different paths to arrive at

point 𝑃. If the maximum destructive interference is

to occur at point 𝑃, the two beams must travel paths

that differ by _______.

a)

a whole number of wavelengths

b)

a whole number of half-wavelengths

c)

an odd number of wavelengths

d)

an odd number of half-wavelengths

18.
What is meant by monochromatic light?
a)
A light source with one wavelength only
b)
A light source with one speed only
c)
A light source with only white light
d)
A light source that is coherent
19.
It is difficult to get clear young's double slit fringes with white light because
a)
The frequency of white light is too high
b)
The wavelength of white light is too low
c)
the different colour fringes overlap
d)
white light is not bright enough
20.

Which of the following statements is untrue when applied to Young's double slit pattern

a)

The fringes are equally spaced

b)

A bright fringe occurs when the waves arrive in phase

c)

The sources must be coherent

d)

The centre fringe is the brightest

21.
When a wave bends around a barrier or passes through an opening, it is called
a)
Diffraction
b)
Reflection
c)
Refraction
d)
Interference
22.
For the greatest amount of diffraction to occur when a wave reaches a barrier, the barrier must be
a)
A. larger than the wavelength.
b)
B. at least twice the size of the wavelength.       
c)
C. the same size or smaller than the wavelength.
d)
D. the exact same size as the wavelength.
23.

Which diagram best represents the shape and direction of a series of wave fronts after they have passed through a small opening in a barrier?

a)
b)
c)
d)
24.
Which of the following will increase the spacing of Young's double slit fringes
a)
A blue light is used instead of a red light
b)
the screen is moved closer to the slits
c)
the slits are moved closer together
d)
Each slit is made wider
25.
Which of the following has no effect on the spacing of Young's double slit fringes
a)
Changing the wavelength 
b)
Changing the frequency
c)
Moving the screen further away
d)
Changing the size of each slit
26.
Which of the following statements is untrue when applied to young's double slit pattern
a)
The fringes are equally spaced
b)
a bright fringe occurs when the waves arrive in phase
c)
the sources must be coherent
d)
The bright and dark bands are the same width
27.
A red light has a wavelength of 650nm.
It is shone through a double slit spacing 0.2mm onto a screen 2m away.
The fringe spacing is?
a)
6.5 x 10 -6 m
b)
1.6 x 10-3 m
c)
6.5 x 10-3 m
d)
1.6 x 10-6 m
28.
A red light of wavelength 650 nm is used with a diffraction grating with 500 lines per mm.
How many diffraction maxima will be seen in total
a)
1
b)
3
c)
5
d)
7
29.
Which of the following will decrease the spacing of Young's double slit fringes
a)
Increasing the frequency of the waves
b)
moving the screen further away
c)
decreasing the distance between the slits
d)
Using narrower slits
30.
Which of the following will increase the spacing of the interference fringes
a)
Moving the screen closer
b)
Increasing the number of slits
c)
Using more slits per mm
d)
Using a higher frequency