Ch.27 PHY

What is a light with a single wavelength called?

Monochoromatic

What is the principle of Linear Superposition?

The resultant disturbance at any point is the sum of the disturbance from individual waves.

What was Young’s Double Slit experiment?

If a light behaves as a wave, it will produce interference effects

What is an interferometer? (michelson interferometer)

A device used to measure the wavelength of light by analyzing the interference between two light waves.

What kind of interference is this?

Constructive

What kind of intereference is this?

Destructive

Whats Huygen’s Principle?

Every point on a wavefront acts as a pointsource.

What is the formula for Young’s Double Slit (constructive)?

𝑑𝑠𝑖𝑛 𝜃 = 𝑚λ (𝑐𝑜𝑛𝑠𝑡𝑟𝑢𝑐𝑡𝑖𝑣𝑒)

What is the formula for Young’s Double Slit soap on glass (destructive)?

𝑑𝑠𝑖𝑛 𝜃 = (𝑚 + 1/2)λ (𝑑𝑒𝑠𝑡𝑟𝑢𝑐𝑡𝑖𝑣𝑒)

What is diffraction grating?

Large number of equally spaced narrow slits

What is thin film interference?

Thickness of a few wavelengths, light will reflect both the top and bottom surfaces of layer causing interference (soap bubbles and oil slicks)

What is the thin-film case 1 formula soap on glass (constructive)?

𝑑 = 𝑚λ / 𝑛𝑓𝑖𝑙𝑚 (𝑐𝑜𝑛𝑠𝑡𝑟𝑢𝑐𝑡𝑖𝑣𝑒 𝑖𝑛𝑡𝑒𝑟𝑓𝑒𝑟𝑒𝑛𝑐𝑒)

What is the thin-film case 1 formula soap bubble (destructive)?

2𝑑 = (𝑚 + 1/2)λ / 𝑛𝑓𝑖𝑙𝑚 (𝑑𝑒𝑠𝑡𝑟𝑢𝑐𝑡𝑖𝑣𝑒 𝑖𝑛𝑡𝑒𝑟𝑓𝑒𝑟𝑒𝑛𝑐𝑒)

What is the thin-film case 2 formula soap bubble (constructive)?

2𝑑 = (𝑚 + 1/2)λ / 𝑛𝑓𝑖𝑙𝑚 (𝑐𝑜𝑛𝑠𝑡𝑟𝑢𝑐𝑡𝑖𝑣𝑒 𝑖𝑛𝑡𝑒𝑟𝑓𝑒𝑟𝑒𝑛𝑐𝑒)

What is case 1 in the thin film theory?

When both reflected rays undergo a phase change (180) and cancel out.

What happens to ray one in case 1?

It reflects off of the soap boundary. Air→ film causing a 180 phase change

What happens to ray two in case 1?

It enters the film and reflects on the bottom (film→glass). 180 phase change.

What happens to ray three in case 1?

It transmitted through the glass

What is the net reflection of case 1?

0-cancel out

What is the brightness of case 1?

2d

What happens to ray one in case 2?

It reflects off the soap boundary (air→film). 180 phase change.

What happens to ray two in case 2?

It enters the film and reflects off the bottom (film→air). No flip since n1>n2

What happens to ray three in case 2?

It’s transmitted to through the bottom.

What is the net reflection of case 2?

½ a wave shift

What is the brightness of case 2?

½ wavelenght shift.

Is light produced if constructive interference is reached? If so, what kind?

Yes, bright fringes produced

Is light produced if destructive interference is reached? If so, what kind?

No

What is the single slit formula?

𝐷𝑠𝑖𝑛 𝜃 = 𝑚λ 𝑚 = ±1, ±2, ±3, …

What are the diffraction grating formulas?

d = 1/N

sin (𝜃𝑚) = 𝑚λ / 𝑑 𝑚 = 0,1,2,…

tan (𝜃𝑚) = 𝑥𝑚/𝐿

What is the formula for Rayleighs criterion?

𝜃𝑚𝑖𝑛 = 1.22𝜆/ 𝐷