Question

A diver in a swimming pool wants to signal his distress to a person lying on the edge of the pool by flashing his water proof flash light

• A. He must direct the beam vertically upwards
• B. He has to direct the beam horizontally
• C. He has to direct the beam at an angle to the vertical which is slightly less than the critical angle of incidence for total internal reflection
• D. He has to direct the beam at an angle to the vertical which is slightly more than the critical angle of incidence for the total internal reflection

Answer 1

Answer: (A), (C)

The correct options are
A

He must direct the beam vertically upwards

C

He has to direct the beam at an angle to the vertical which is slightly less than the critical angle of incidence for total internal reflection

When incident angle is greater than critical angle, then total internal reflection takes place and will come back in same medium. That's how he will be able to flash the light signal to the person at the edge of the pool.