1996 General Studies, all questions
UPSC Prelims 1996 · General Studies
Question 120: Science and Technology
Total internal reflection can take place when light travels from
adiamond to glass
bwater to glass
cair to water
dair to glass
AnswerThe answer is (a).
Total internal reflection happens only when light goes from a denser to a rarer medium and meets the boundary beyond the critical angle. Diamond (refractive index about 2.4) to glass (about 1.5) is denser to rarer. Water to glass, air to water and air to glass all go from a rarer to a denser medium.
Why each option is right or wrong
- (a) Right: diamond to glass goes from a denser to a rarer medium.
- (b) Water to glass goes from a rarer to a denser medium.
- (c) Air to water goes from a rarer to a denser medium.
- (d) Air to glass goes from a rarer to a denser medium.
Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 1996, General Studies. UPSC's own paper isn't online; the words are from a published compilation. The paper on upsc.gov.in.