Total Internal Reflection
3 marks · EasyA ray of light travels from a type of glass (refractive index 1.62) into air.
Write down the equation linking the critical angle and the refractive index of the glass.
Calculate the value of the critical angle, to 2 decimal places.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
(a) sin c = 1/n
(b) 38.18° degree
Common mistakes: Using wrong equation.; Incorrect value for sine.; Rounding errors.
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · States correct equation: sin c = 1/n
M1 (b) · 1 mark · Substitutes n = 1.62 into the equation. (follow-through)
A1 (b) · 1 mark · Evaluates critical angle to 2 decimal places: 38.18° (follow-through)
Worked solution
a) The equation is: sin c = 1/n
b) n = 1.62