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Quick Quiz On Waves:
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Menu]
Give all answers
to 2d.p. unless otherwise asked.
1. The velocity of an electromagnetic
wave is 3.0 *108 m/s. If the frequency of the wave is 8.5 *
1014 Hz, what is its
wavelength to the nearest
nanometre ?
nm
2. If an electromagnetic wave
has a wavelength of 576 nm then
(a) what is its frequency?
x1014Hz
(b) How many whole waves fit into
1mm?
whole
waves
3. If an electromagnetic wave
has a wavelength of 560 nm
which is doppler shifted to
630nm then
(a) what is the recession
speed (to 3d.p) of the
source as a fraction of lightspeed?
fraction
of C
(b) What is this speed in
km/sec ?
km/sec
4. A distant galaxy is receding
from us at a speed of 1.0x108 metres per second. An atomic transition
causes the emission of a 600nm spectral line.
(a) What wavelength
(to nearest nm) will the spectral line appear to be as observed on earth?
nm
(b) What energy transition (in
electronvolts) would give rise to this spectral line ?
eV
5. An atomic transition of 3.10
eV occurs in an atom of a distant star. Calculate the wavelength of the
emitted spectral line in nanometres .
nm
6. An earthbound observer measures
the wavelength of the spectral line from Q5 to be 441 nm .
(a) What is the recession
velocity as a fraction of c ?
fraction
of c
(b) What is the speed in m/sec
?
x108
m/sec
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