When light moves from a medium with higher refractive index to a medium with lower refractive index, the critical angle is the angle above which there is no refracted ray, and it is given by:

(2)
where

is the refractive index of the second medium and

is the refractive index of the first medium.
We can find the ratio

by using Snell's law:

(1)
where

is the angle of incidence

is the angle of refraction
By using the data of the problem and re-arranging (1), we find

and if we use eq.(2) we can now find the value of the critical angle:
Answer:
Given the area A of a flat surface and the magnetic flux through the surface
it is possible to calculate the magnitude
.
Explanation:
The magnetic flux gives an idea of how many magnetic field lines are passing through a surface. The SI unit of the magnetic flux
is the weber (Wb), of the magnetic field B is the tesla (T) and of the area A is (
). So 1 Wb=1 T.m².
For a flat surface S of area A in a uniform magnetic field B, with
being the angle between the vector normal to the surface S and the direction of the magnetic field B, we define the magnetic flux through the surface as:

We are told the values of
and B, then we can calculate the magnitude

Answer:
0.003034 s
1.035 m
4.5 m
Explanation:
= frequency of the tone = 329.6 Hz
= Time period of the sound wave
we know that, Time period and frequency are related as

= speed of the sound in the air = 341 ms⁻¹
wavelength of the sound is given as

= speed of the sound in the water = 1480 ms⁻¹
wavelength of the sound in water is given as

Explanation:
It is given that,
Magnetic field, B = 0.15 T
Charge on a proton, 
Mass of a proton, 
The cyclotron frequency is given by :


f = 2286785.40 Hz
or


Hence, this is the required solution.
The acceleration of the car is solved by subtracting the initial speed from the final speed then dividing the result by the elapsed time.
initial speed = 72 km/hr = 20 m/s
final speed = 0 m/s
elapsed time = 5 seconds
acceleration = (0 m/s – 20 m/s) / 5 s
acceleration = - 20m/s / 5 s
acceleration = -4 m/s^2