You shine a flashlight on a pond. the light hits the pond at an angle of 70° to the normal of the pond. what is angle between the refracted ray entering the pond and the surface normal of the pond? the index of refraction of water is 4/3 select one of the following: (a) 86.99 (b) 23.4° (c) 35 (d) 44.8 (e) toby

(d)  44.8°

Explanation:

For refraction,  

Using Snell's law as:

Where,  

Θ₁ is the angle of incidence  

Θ₂ is the angle of refraction

n₁ is the refractive index of air which is 1

n₂ is the refractive index of water which is 4/3

Given that angle of incidence = 70°

So,  

Angle of refraction = sin⁻¹ 0.7048 = 44.8°.

weight of the box is given as

here this is placed on the inclined of angle 42 degree

now this weight will have two components one is along the incline other is perpendicular to it

so here we need to apply a force parallel to incline opposite to its component of weight

so here the component of weight is given as

here we have

so it requires 75 n force to move it upwards