A soap film in a wire lop is held vertical and viewed under
sunlight. The top...
A soap film in a wire lop is held vertical and viewed under
sunlight. The top part of the film appears black. With the aid of a
diagram, explain, in details, why.
A soap film (n = 1.33) is formed in a loop of wire that is
mounted vertically is not exactly uniform in thickness because of
its weight, but wedge-shaped in cross section. When the film is
illuminated with violet light of wavelength 405 nm, one sees that a
distance of 2.20 cm separates two bright fringes that are 4 orders
apart. By how much does the film differ in thickness over this
distance?
The upper end of a vertical steel wire 4mm diameter and 2,5 m
long is held securely. The other end is fixed central to a steel
cylinder, 80 mm diameter and of density 7,8 Mg/m3, arranged with
its axis vertically. Determine the length of the cylinder to give
0,6 torsional vibration per second.
A soap film (n=1.33) is 772 nm thick. White light strikes the
film at normal incidence. What visible wavelengths will be
constructively reflected if the film is surrounded by air on both
sides? If there is more than one answer, separate them by a
comma.
a) A soap film appears invisible when it approaches a
zero-thickness.
In 50 words and/or a figure, explain why.
[1] b) The north pole attracts the south pole of a compass needle
allowing navigation. T/F
[1] c) There are 3 colour sensors in the eye with maximum
responsivity centered on the
primary colours red, yellow and blue. T/F
[1] d) A “red/green colour blind” person is able to detect only red
or green light, not the
other. T/F
[2] e)...
A thin film of soap solution (n = 1.33) has air on either side
and is illuminated normally with white light. Interference minima
are visible in the reflected light only at wavelengths of 480, 520,
and 1040 nm in air.
What is the minimum thickness of the film?
A thin film of soap with n = 1.35 hanging in the air reflects
dominantly red light with ? = 620 nm. What is the minimum thickness
of the film?
Now this film is on a sheet of glass, with n = 1.46. What is the
wavelength of the light in air that will now be predominantly
reflected?
A thin film of soap solution (n = 1.33) has air on either side
and is illuminated normally with white light. Interference minima
are visible in the reflected light only at wavelengths of 480, 520,
and 1040 nm in air.
What is the minimum thickness of the film? (Express your
answer to two significant figures.)
A thin film of oil (n = 1.28) is located on smooth, wet
pavement. When viewed from a direction perpendicular to the
pavement, the film reflects most strongly red light at 640 nm and
reflects no light at 427 nm. What is the minimum thickness of the
oil film?
nm
You viewed the film, North Country. Discuss one moral and one
ethical breach by the company. For each breach, provide a suggested
remedy that would protect the company from liability. Provide URL
for all Internet sources
A jumper with a mass of 90 kg is held at rest at the top of a
100 m high ramp. The jumper is then released to water. (The
gravitational field strength is 9.8 m/s2 )
Calculate the change in gravitational potential energy of the
jumper when he reaches the ground (the point Y) in kilojoule. How
would you calculate the magnitude of kinetic energy of the jumper
at point Y? (Assume no energy is transferred or lost during). A...