Part 3: long answer questions

3.1. A monochromatic light falls on two very narrow slits 0.038 mm apart. Successive fringes on a screen 6.5 m away are 5.0 cm apart near the center of the pattern. Determine the wavelength of the light[EG7]; (3)

3.2. Monochromatic light with wavelength λ = 650 nm is incident normally on a diffraction grating containing 6500 lines per centimeter.[EG8]

a. Find the angle at which the second-order maxima is observed; (3)

b. Show and explain briefly that the third-order maxima is NOT observed for this situation; (3)

3.3. Two stars have the same size but one has a temperature that is four times larger. How much more energy per second does the hotter star radiate.[EG9] (3)

3.4. The sun has an approximate black-body spectrum with most of the energy radiated at a wavelength of 5.0 × 10^–7 m. Find the surface temperature of the sun?[EG10] (3)

[Total: 12 ]

[END OF EXAMINATION]