12.3

Question 1

What is monochromatic light

Answer 1

Single wavelength, single frequency

Question 2

Describe the method of the Young double-slit experiment

Answer 2

• Monochromatic light source (used colour filter)
• Diffracted through narrow single slit
• Diffracting light arrives in phase at double slit
• Diffracts again from double slit
• Each slit acts as coherent wave source
• Waves overlap, forms interference pattern
• Appears as alternating bright and dark fringes (maxima and minima)

Question 3

What is the double-slit experiment formula for wavelength

Answer 3

λ = ax / D

λ - wavelength [m]

a - separation between two slits [m]

x - separation between two fringes [m]

D - distance from slits and interference pattern [m]

Question 4

What is the condition for the forumla for wavelength (double-slit)

Answer 4

• a &laquo_space;D

* Distance between slits is Much Smaller than distance between slits and interference pattern

Question 5

What can the formula for wavelength (double-slit) be used for

Answer 5

• Wavelength of wave producing an interference pattern due to double slit

• Wavelength of coherent sources producing an interference pattern
-two loudspeakers connected to same signal generator

• Wavelength of monochromatic light from laser passed through double slit producing an interference pattern
-single slit is not needed since light is already monochromatic + in phase