Check Test - Diffraction and interference
1 Huygens' principle requires that ...
a ... waves bend into a region behind a barrier.
d ... the end of a barrier acts as the source of new waves.
2 The bending of sound waves into a shadow region behind a wall is called ...
... diffraction.
3 A student is attempting to photograph a single slit interference pattern in a ripple tank. He has a straight wave generator and a gap in a wall.
He is most likely to succeed with ...
... a wavelength of 1 cm and a gap width of 3 cm.
4 The man who is credited with the first detailed observation of interference fringes using sunlight is...
... Young
5 Waves can be made in a ripple tank by hand with a roller (broom handle) or with a vibrator.
What is the most compelling reason to use a vibrator for selected demonstrations?
The wave generator vibrates at higher frequencies to produce regular waves with shorter wavelengths.
6 A student is looking at a photograph of nodal lines in a two source interference pattern made in a ripple tank.
She notices that ....
... waves on adjacent lines of reinforcement are 180° out of phase.
7 The amplitude of waves on a line of reinforcement in a two source interference pattern in a ripple tank is, (in terms of the amplitude A of one of the identical single wave trains), equal to....
... 2A
8 The amplitude of waves radiating from a point source in a ripple tank depends on some function of the distance (r) from the source.
The amplitude is ...
... proportional to one over the square root of r.
9 A student is observing interference fringes by looking at a distant point source of light through two closely spaced slits. He sees a horizontal series of bright spots (fringes).
He notices that the fringes move closer together when ...
... he uses slits that are further apart.
10 The fringes seen with a diffraction grating are separated by much larger angles than the fringes seen with a pair of closely spaced slits because ...
... the slits on the grating are closer together.
11 A student observes the pattern of fringes when looking at a distant line filament bulb through a narrow single slit. He notes the apparent separation of the fringes. He then moves closer to the light source.
The fringes now appear ...
... brighter and closer together.
12 A moire pattern which models the two source interference pattern is shown actual size.
The wavelength of the waves that are modeled is closest to ...
... 2 mm
13 A student notices a rainbow type 'reflection' when a CD is lying on a table near a lit candle.
Which one of the following completed statements is incorrect.
.The 'rainbow' cannot be formed by the candle flame.
14 A red filter is placed over a filament bulb and interference fringes are observed. The red filter is replaced by a green filter.
The pattern now appears to be ...
... a little smaller.
15 The first order spectrum is observed at a displacement of q ° through a transmission diffraction grating with a line separation d.
The wavelength of the light l is given by ...
... l = d sinq
16 A five line grating is used to display a diffraction pattern on a wall using a small red laser beam. Tiny spots appear between the expected interference fringes. When the grating has five lines the number of tiny spots between each main fringe is ...
... 3.
17 Which of the following completed statements is incorrect?
When compared to the fringes seen through a closely spaced double slit the fringes seen through a diffraction grating with the same line separation and width are ...
... more widely separated.
18 A picket fence with boards that are 10 cm wide, with spaces that are 10 cm wide, acts as a diffraction grating for a monophonic tone generated by a signal generator. The first order spectrum is a single peak in intensity at a separation of 30°.
The wavelength of the sound is closest to ...
... 10 cm
19 The separation of atoms in a typical metal crystal is closest to ...
... 0.1 nm
20 The images of two stars in a telescope are just resolved by Rayleigh's criterion.
The images can be described as two overlapping circular ripple patterns.
21 A student is not able to resolve two distant yellow car headlights at night when he looks carefully with both eyes open.
Which of the following statements is correct?
He is more likely to resolve the headlights if they were red.
22 The property that makes acute hearing an ideal early warning system for land-based animals is ...
... greater diffraction when compared to light.
23 The velocity of sound is greatest in ...
... diamond.
24 The size of a diffraction halo seen around the moon at night when viewed through thin high level cloud ...
... depends on the wavelength of the light and the droplet size in the cloud.
25 Which statement is the most appropriate, given our current understanding?
The laws of physics are simplified models of the physical world.
You may find it helpful to print this check test