(a) 
The frequency of a wave is given by:
where
v is the wave's speed
is the wavelength
For the red laser light in this problem, we have
(speed of light)
Substituting,
(b) 427.6 nm
The wavelength of the wave in the glass is given by
where
is the original wavelength of the wave in air
n = 1.48 is the refractive index of glass
Substituting into the formula,
(c) 
The speed of the wave in the glass is given by
where
is the original speed of the wave in air
n = 1.48 is the refractive index of glass
Substituting into the formula,
Answer: Mid-ocean ridges are geologically important because they occur along the kind of plate boundary where new ocean floor is created as the plates spread apart. Thus the mid-ocean ridge is also known as a "spreading center" or a "divergent plate boundary." The plates spread apart at rates of 1 cm to 20 cm per year.
Coal is burned to get energy. By burning coal, green houses gases like carbon dioxide, nitrogen oxides and suphur oxides are produced.
Rest of the energy sources given in the option are clean energies.
Answer is A.
Thew energy stored in a capacitor of capacitance 
and voltage between the plates 
is
.
Substituting numerical value
Supposing the runner is condensed to a point and moves upward at 2.2 m/s.
It takes a time = 2.2/g = 2.2/9.8 = 0.22 seconds to increase to max height.
Now looking at this condition in opposite - that is the runner is at max height and drops back to earth in 0.22 s (symmetry of this kind of motion).
From what height does any object take 0.22 s to fall to earth (supposing there is no air friction)?
d = 1/2gt²= (0.5)(9.8)(0.22)²= 0.24 m
