# Light- critical angle/refraction/reflection

I am stuck on three questions :(
Formulas: nsin(x)=n sin (x)
sinx=n2/n1

1. A ray of light traveling in air strikes the surface of a liquid. If the angle of incidence is 26.0◦ and the angle of refraction is 19.3◦, ﬁnd the critical angle for light traveling from the liquid back into the air.
This is my work so far:
1sin(26)=xsin(19.3)
x=1.326

sinx=1.326/1
I then get an error. I do not know what I'm doing wrong :(

2. A ray of light traveling in air strikes the surface of a block of clear ice (n = 1.309) at an
angle of 58.4◦ with the normal. Part of the light is reﬂected and part is refracted. Find the angle between the reﬂected and the refracted light.
Work so far:
1sin(58.4)=1.309sinx
x=40.59213054
I believe that this is the refracted angle, but what is the reflected angle/how do I find it?

3. A submarine is 316 m horizontally out from the shore and 120 m beneath the surface of
the water. A laser beam is sent from the submarine so that it strikes the surface of the
water at a point 223 m m from the shore. If the beam strikes the top of a building
standing directly at the water’s edge, ﬁnd the height of the building. The index of refraction of water is 1.333.
Work so far: None, because I can't even comprehend it.

Related Introductory Physics Homework Help News on Phys.org
I figured out 1 and 3, can someone help me with number two though?

I figured out 1 and 3, can someone help me with number two though?
Great! So for (2),

2. A ray of light traveling in air strikes the surface of a block of clear ice (n = 1.309) at an
angle of 58.4◦ with the normal. Part of the light is reﬂected and part is refracted. Find the angle between the reﬂected and the refracted light.
Work so far:
1sin(58.4)=1.309sinx
x=40.59213054
I believe that this is the refracted angle, but what is the reflected angle/how do I find it?
What is the relation between angle of incidence and reflection for any plain mirror? 