Answer:
1.30
Explanation:
To calculate the critical angle we have ti use the formula:

where theta_c is the critical angle, n1 is the index of refraction of the material where the light is totally reflected, and n2 is the refractive index of the other material.
By taking n_2 and replacing we obtain:

hope this helps!!
Answer: 704
Explanation:Vi = 0 m/s
vf = 65 m/s
a = 3 m/s2
d = ??
vf2 = vi2 + 2*a*d
(65 m/s)2 = (0 m/s)2 + 2*(3 m/s2)*d
4225 m2/s2 = (0 m/s)2 + (6 m/s2)*d
(4225 m 2/m2)/(6 m/s2) = d
d = 704 m
I think comets because they are small and they are composed of ice or water. Hope it helps :)
We are given
r = 0.6 m
n = 1.5
D = 0.6 m, R1 = 30 cm
R2 = 120 cm
We are asked to get the focal length and the distance of the focal plane from the lens
We use the formula
1 / f = ( n - 1) (1/R1 - 1/R2)
Substituting and solving for f
1/ f = (1.5 - 1) (1/30 - 1/120)
f = 80 cm
The focal length is 80 cm and the distance of the focal plane from the lesn is 80 cm - 30 cm = 50 cm.<span />