Question

1. Two waves of the same wavelength interfere - in which case(s) below, will the two waves experience fully destructive interference? (Note: π is "pi")

A) the two waves are 90o degrees apart in phase

B) the two waves are 2π radians apart in phase

C) the two waves are π radians apart in phase

D) the two waves are 1.5 wavelengths apart in phase

E) the two waves are one wavelength apart in phase

F) the two waves are three wavelengths apart in phase

G) the two waves are a half wavelength apart in phase

2. What quantity/quantities change when a light wave move from air to water, and how does it/do they change? (Select all that apply.)

A) its frequency decreases

B) its wavelength decreases

C) its speed increases

D) its speed decreases

E) its wavelength increases

F) its frequency increases

3. The phase of a wave changes by 180 degrees (i.e., the wave flips) at a boundary when:

A) it travels from a lower n to a higher n medium

B) it reflects off a lower n medium

C) it travels from a higher n to a lower n medium

D) it reflects off a higher n medium

4. You are looking at thin film interference due to a piece of glass (n = 1.50) sitting on top of water (n = 1.33). Which of these n values would you use in formulas 17.14 & 17.15 and how many phase changes are you dealing with in this problem?

A) n of water, 0 phase changes

B) n of glass, 1 phase change

C) n of water, 2 phase changes

D) n of water, 1 phase change

E) n of glass, 0 phase changes

F) n of glass, 2 phase changes

Answer 1

1. Two waves of the same wavelength interfere - in which case(s) below, will the two waves experience fully destructive interference? (Note: π is "pi")

C) the two waves are π radians apart in phase

D) the two waves are 1.5 wavelengths apart in phase

G) the two waves are a half wavelength apart in phase

2. What quantity/quantities change when a light wave move from air to water, and how does it/do they change? (Select all that apply.)

B) its wavelength decreases

D) its speed decreases

3. The phase of a wave changes by 180 degrees (i.e., the wave flips) at a boundary when:

D) it reflects off a higher n medium

4. You are looking at thin film interference due to a piece of glass (n = 1.50) sitting on top of water (n = 1.33). Which of these n values would you use in formulas 17.14 & 17.15 and how many phase changes are you dealing with in this problem?

B) n of glass, 1 phase change