Supplemental Questions
In a ripple tank, a point on the third nodal line from the centre is 35.0 cm from one source and 42.0 cm from another. The
sources are 11.2 cm apart and vibrate in phase at 10.5 Hz. Calculate the wavelength and the speed of the waves.
Two very small, identical speakers, each radiating sound uniformly in all directions, are placed at points S₁ and S₂. The
speakers are connected to an audio source in such a way that they radiate in phase, at the common wavelength of 2.00 m.
Sound propagates in air at 338 m/s.
(a) Calculate the frequency of the sound
(b) Point M, a nodal point, is 7.0 m from S₁ and more than 7.0 m from S₂. Find these three possible distances M could
be from S₂
(c) Point N, also a nodal point, is 12.0 m from S₁ and 5.0m from S₂. On which nodal line is N located?
A student performing Young’s experiment with a single-colour source finds the distance between the first and the seventh
nodal lines to be 6.0 cm. The screen is located 3.0 m from the two slits. The slit separation is 2.2x10² μm. Calculate the
wavelength of the light.
Single-colour light falling on two slits 0.042 mm apart creates a 3.8 degree angle between the right bisector and the fifth
minimum. Calculate the wavelength of the light.
An interference pattern is formed on a screen when helium-neon laser light (λ= 6.3x10ˉ⁷ m) is directed toward it through
two slits. The slits are 43 μm apart. The screen is 2.5 m away. Calculate the separation of adjacent nodal lines.
1. The wavelength of orange light is 6.0x10ˉ⁷ m in air. Calculate its frequency.
2. Light from a certain source has a frequency of 3.80x10¹⁴ Hz. Calculate its wavelength in air, in nanometres.
3. A certain shade of violet light has a wavelength in air of 4.4x10ˉ⁷ m. If the index of refraction of alcohol relative
to air for violet light is 1.40, what is the wavelength of the violet light in alcohol?
A beam of light of wavelength 5.50x10² nm falls on a screen containing a pair of narrow slits separated by 0.10 mm.
Calculate the separation between the two seventh-order maxima on a screen 2.00 m from the slits.
What are the three smallest thicknesses of a soap bubble capable of producing reflective destructive interference for light
with a wavelength of 645 nm in air? (Assume that the index of refraction of soapy water is the same as that of pure water,
1.33)
A coating, 177.4 nm thick, is applied to a lens to minimize reflections. The respective, indexes of refraction of the coating
and of the lens material are 1.55 and 1.48. What wavelength in air is minimally reflected for normal incidence in the
smallest thickness? Draw a diagram as part of your solution.