•6. See the below diagram and answer when does constructive interference occur? 

a) The two waves of light above travel the same distance before they arrive at the screen. They constructively interfere because both go the   (2 words) and arrive (2 words).

b)   (2 words) is light that is totally in-phase. Light produced by a (1 word) is an example of totally in phase light.

7. Is there any other condition needed for constructive interference to occur? Yes,  when the  (2 words) is a (2 words), multiple of a wavelength of the wave.

 

•8. When does destructive interference occurs?

 The waves destructively interfere because they arrive at the screen (3 words) by . When the path difference is a odd multiple of the half wavelength (1/2, 3/2, 5/2, etc.)    •

9. Why can we assume that the light rays emerging from each slit are essentially parallel? Because the (4 words) is very small compared to the   (4 words).

 

•10. a) What is the extra distance (path difference) δ (delta) one light ray cover, equal to?

• 

    (formula)

 

•b) What is the mathematical condition for the constructive interference to occur? (formula)

 

•c) What is the mathematical condition for the destructive interference to occur? (formula)

d) n = 1,2,3,.....is called the (5 words).

e) The first order fringes (n=1) occur on either side of the (3 words); the second order fringes (n=2) occur on either side of the (3 words), etc.

11.  How does the intensity of the bright lines (or fringes) change?

a) The intensity of the bright lines is   (1 word) for the central bright spot and (1 word) for the higher orders.

b) When light interferes, the light waves produce alternating bright and dark bands of colors called 2 words; nodal lines appear as (2 words) and antinodal lines appear as (2 words ).

c) Violet light (with the shortest wavelength) is the (1 word) diffracted and red light (with the longest wavelength) is the (1 word) diffracted.

12. a) The position of the fringe depends upon the (1 word) of light, except the (3 words), which appears as the original,   (1 word) light.

b) The (1 word) order fringes, contain a spectrum of the light colors comprising the original light. Their (1 word) depends upon their wavelength. Young's experiment proved that light behaves as a  (1 word).

Single Slit Diffraction

13. Light passes through a small slit and falls on a screen so far away that the light rays emerging from the slit are considered to be (1 word). Light rays that pass straight through are all (2 words) and produce a central bright spot of (1 word) light.

 

14. The light ray traveling through the center of the slit will travel more than that of one emerging from the top of the slit. This ray coming from the center of the slit will (2 words) with the ray passing through the top of the slit. Each ray passing through the bottom half of the slit will (1 word) with a corresponding ray passing through the top half. The rays (1 word) interfere in (1 word). Thus, (3 words) the screen.

15. a) Dark bands occurs at angles given by

(formula)

 

where D is the (2 words) and n =

 

b) Broad bands (areas of light) occur at angles given by

(formula) 

 

where D is the slit width and m =

 

16. Single slit diffraction differs from double slit in that patterns have a (3 words) and (2 words) are produced.

 

D sinq = n l locates the position of minima for n=1,2,3,etc. When n=0, the strongest maxima - the (3 words) - occurs. Between the minima, smaller intensity maxima occur. (Notice - the (1 word) for a single slit diffraction pattern satisfy the criteria for a (1 word)  for a double slit pattern.)

The image below shows a graph of intensity vs position for a single slit diffraction pattern. Notice the wide (2 words) and the much less intense (2 words).

Diffraction Grating

D = meters/line