Explain the change to the appearance of the interference pattern when the red-light laser is replaced by one that emits green light.
green wavelength smaller than red
fringe separation / distance between maxima decreases
One of the slits is now covered. Describe the appearance of the pattern on the screen.
bright central maximum
subsidiary maxima «on either side»
the width of the central fringe is twice / larger than the width of the subsidiary/secondary fringes/maxima
**OR **
intensity of pattern is decreased
Outline what is meant by the principle of superposition of waves.
when 2 waves meet the resultant displacement
is the «vector» sum of their individual displacements
Red laser light is incident on a double slit with a slit separation of 0.35 mm. A double-slit interference pattern is observed on a screen 2.4 m from the slits. The distance between successive maxima on the screen is 4.7 mm. Calculate the wavelength of the light. Give your answer to an appropriate number of significant figures.
