Question

27.Consider the path of a ray of light passing through a rectangular glass slab for different angles of incidence.(i) Which one is greater: angle of incidence or angle of refraction? (ii) What happens to the emergent angle on increasing the incident angle at air-glass interface? (iii) State the conditions when no refraction occurs.2ORSunita takes a mirror which is depressed at the centre and mounts it on a mirror stand. An erect and enlarged image of herface is formed. She places the mirror on a stand along a meterscale at 15 cm mark. In front of this mirror, shemounts a white screen and moves it back and forth along the meterscale till a sharp, well-defined inverted image of a distant treeis formed on the screen at 35 cm mark.(i)Name the mirror and find its focal length.(ii) Why does Sunita get sharp image of the distant building at 35 cm mark

Answer 1

I know answer but not confirmed

Answer 2

Welcome friend,

● Answer -
1) We know Snell's law,
n = sini / sinr
Here n = 1.5,
∴ sini > sinr
∴ i > r

Hence, angle of incidence is greater than that of refraction.

2) For refraction through a rectangular slab, emergent angle is same as incident angle.

Hence, angle of emergence increases on increasing angle of incidence.

3) Conditions when no refraction occurs -
i) When both media have same refractive index
ii) When angle of incidence is zero.

Hope this helped you...