14) What happens to a light wave with velocity v N when it travels from air into

Question

14) What happens to a light wave with velocity v N when it travels from air into glass with refraction wavelength and fis the frequency, ofthe light. Choose from the answers provided below. (a) Its speed remains the same; (b) Its speed decreases (c) Its wavelength increases (d) Its wavelength decreases. (e) (b) and (d). 15) Consider the interface shown in Fig. 7 below. This figure shows the interface between air and an anti-reflective thin film coating of MgF2 with n 1.52. n" 1.38), that is deposited on top of a 1 mm thick glass substrate Assuming that the incident ray has wavelength 550 nm, calculate the critical thickness required for the antireflective MgF2 coating. Choose from the answers provided below. a) 25.2 nm b) to 99.64 nm c) to 200 nm d) to 32.5 nm e) Not possible. "Nonreflectir MgF2 Film glass film n air Air MgF2 Film Glass Fig.-7: Schematic for problem tk15

Explanation / Answer

Number 14)

The formula for the wave is v = f(wavelength)

In a thicker medium, the speed decreases. Since speed decreases, the wavelength decreases since the frequency can't change.

Thus the answer is Choice E

Number 15)

Apply 2nt = (m+.5)(wavelength)

2(1.38)(t) = (.5)(550 X 10-9)

t = 99.64 nm - Choice B

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.