DIFFRACTION GRATINGS AND DOUBLE SLITS

Question 1

What two conditions must be met in order to measure wavelength in double slit experiment

Answer 1

• light must be monochromatic (all have the same wavelength)
• accurate way of producing small path differences

Question 2

describe the double slit experiment

Answer 2

monochromatic light leaves a source, entering the slit diffraction makes the wave fronts circular, and enters a double slit diffraction occurs at both slits. the wave comes from a coherent source so the waves overlap in interfere. the monochromatic light will reach the screen in phase showing red, and out of phase will be dark.

Question 3

what is the equation for working out the wavelength from a light source, and two condition necessary

Answer 3

λ=ax/d

a has to be smaller than d, or ø from the central fringe has to be over 10º

Question 4

what is a diffraction grating

Answer 4

optical equipment made from glass, with thousands of thin parallel spaced grooves.

Question 5

why are multiple slits better than 2

Answer 5

improves the brightness and sharpness of the maxima. the maxima are also further apart. so the angle can be measured

Question 6

what is the 0th order maxima

Answer 6

the brightest spot of light, in the middle

Question 7

what is the diffraction grating equation

Answer 7

n λ=dsinø

d is the distance between the slits
ø is the angle from the middle line to the 1st order for example.
n is the order (1,2,3,…)