1. A water wave is incident on a breakwater as sketched below. Use Huygen’s principle to make a careful sketch the form of the waves on the back side of the breakwater.

2. A water wave is incident on a breakwater as sketched below. Huygen’s principle has been used to make a careful sketch of the form of the waves on the back side of the breakwater. The dotted lines represent the peaks of Huygens waves from the lower opening. Is the interference along Path I Path II Path III (a) constructive (b) destructive (c) Not enough information to tell

3. The top drawing was used to determine the angles 2 at which dark fringes occur, since any two waves #1 and #2 which originate from positions a/2 apart in the slit are out of phase by 8 /2. Can the lower drawing be used to determine the angles " for the bright fringes, where the waves shown also originate from positions a/2 apart? (a) Yes. Any 2 waves such as #1 and #2 are in phase. (b) No. A wave originating halfway between #1 and #2 would cancel wave #1. (c) No. Amplitudes of the waves #1 and #2 are different.

4. For a 2 slit interference pattern, rays A and B shown coming from the 2 slits below If point P at the screen is dark is B’s path length a)the same as A’s b)longer by where n = odd integer c) longer by where n = even integer d) none of the above

5. For a 2 slit interference pattern, rays A and B shown coming from the 2 slits below If point P at the screen is dark, B’s path length is longer than A’s path by approximately

6. What is the thickness d of the air film for the 2 nd bright ring from the center? Newton’s Rings Apparatus

7. Two glass slides are touching at one side to make a wedge between them. The wedge is filled with oil of index of refraction 1.6, the glass has an index of 1.5. The glass is illuminated from above with light of wavelength 8 and viewed from above Which of the following expressions gives the thickness t where the first bright fringe from point P is observed?