Question

Physics lenses/critical angle question need help ASAP

Answer 1

The answer should be B.

There are 2 conditions for total internal reflection:

• Light travels from an optically denser medium to an optically less dense medium.
• Angle of incidence (the angle between the incident ray and the normal) is greater than the critical angle.

For this question, light is travelling from glass to air, so the first condition is fulfilled. Yet, the angle of incidence is only 30°, which is less than the critical angle. Therefore, total internal reflection will not occur.

Instead, there will be refraction. Light ray bends away from normal when it is travelling to a less dense object, thus having a greater angle of refraction than the angle of incidence.