(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,
The standard unit is KW/hr, = 1,000W/hr.
(85 + 60) = 145W.
You need to find its fraction of 1,000W., so (145/1000) = 0.145 KWH.
(0.145 x 10p) = 1.45p. per hr.
Answer:
Explanation:
Call the bike on the right A
Call the bike on the left B
The car begins it's time when it passes A
4 minutes later, it passes B.
But B has moved in 4 minutes and that is the key to the problem.
How far has B moved.
t = 4 minutes = 4/60 hours = 1/15 of an hour.
d = ?
rate = 30 km / hr
d = r * t
d = 30 km/hr * 1/15 hours = 2 km
The distance between the bikes is 5 km.
So the car has traveled 5 - 2 = 3 km
d = 3 km
r = ?
t = 4 minutes = 1/15 hour
r = d/t = 3/(1/15)= 3 / 0.066666666 = 45 km/hr.
