Physics
The diagram below shows a light source P embedded in a rectangular glass block ABCD of critical angle 42°. The ray PQ would:
![The diagram below shows a light source P embedded in a rectangular glass block ABCD of critical angle 42°. Complete the path of the ray PQ till it emerges out of the block. [Write necessary angles.] ICSE 2019 Physics Solved Question Paper.](https://cdn1.knowledgeboat.com/img/abp10/5/icse-2019-physics-question-paper-solved-2e-1200x730.png)
- pass undeviated
- suffer refraction
- suffer reflection
- suffer total internal reflection
Answer
suffer total internal reflection
Reason — We can see from the below diagram that the ray is travelling from a denser to a rarer medium and the angle of incidence is greater than the critical angle. In such a case no refracted ray is obtained and the incident ray is reflected back into the same medium. This phenomenon is known as total internal reflection.
![The diagram below shows a light source P embedded in a rectangular glass block ABCD of critical angle 42°. Complete the path of the ray PQ till it emerges out of the block. [Write necessary angles]. ICSE 2019 Physics Solved Question Paper.](https://cdn1.knowledgeboat.com/img/abp10/5/icse-2019-physics-question-paper-solved-2e-completed-diagram-1200x821.png)
Related Questions
Which of the following figures will depict deviation of ray of light A through 180°
In the figure given below, the ray PQ emerging from the object P is refracted along QS. The angle PQN is known as:
- angle of deviation
- angle of refraction
- critical angle
- none of the above
The phenomenon used to transmit a light signal over a wide range in optical fibre is:
- reflection
- refraction
- reflection and refraction
- total internal reflection
In the process of total internal reflection, …………… of energy (or intensity) of light is reflected back.
- 70%
- 80%
- 100%
- 50%