The diagram shows light incident on the centre of a semi circular glass block - Edexcel - GCSE Physics - Question 6 - 2016 - Paper 1
Question 6
The diagram shows light incident on the centre of a semi circular glass block. Angle X is less than the critical angle.
Complete the sentence by putting a cross (✗)... show full transcript
Worked Solution & Example Answer:The diagram shows light incident on the centre of a semi circular glass block - Edexcel - GCSE Physics - Question 6 - 2016 - Paper 1
Step 1
Complete the sentence by putting a cross (✗) in the box next to your answer.
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The ray of light emerges from the glass block along the path towards C.
Step 2
Complete the diagram to show what happens to the ray of light after it reaches the surface of the glass at point P.
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The ray will undergo total internal reflection since angle Y is greater than the critical angle. Therefore, draw the ray reflecting back into the glass.
Step 3
Explain why the light changes direction when it passes from air into the glass lens.
96%
101 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Light changes direction due to refraction, which occurs when light passes from one medium to another. In this case, the speed of light decreases as it enters the denser glass medium from the less dense air, causing the ray to bend towards the normal.
Step 4
Calculate the power of this lens.
98%
120 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The power of a lens (P) is calculated using the formula: P=f1
where f is the focal length in meters. Substituting the values: P=0.251=4.0D
Step 5
Discuss what is happening to the light in each example.
97%
117 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
In the fibre optic lamp, light travels through a fiber due to total internal reflection, allowing it to transmit light efficiently even over long distances. In the plane mirror example, light reflects off the surface, changing its direction while maintaining the angle of incidence equal to the angle of reflection.
