2006 General Studies, all questions

UPSC Prelims 2006 · General Studies

Question 148: Science and Technology

Which one of the following is printed on a commonly used fluorescent tube light?

a220 K
b273 K
c6500 K
d9000 K

AnswerThe answer is (c).

Fluorescent tube lights are marked with their colour temperature, such as 6500 K for the common daylight white tube (and lower figures like 2700 K for warm white). Of the options, 6500 K is the tube rating. 220 is the usual mains voltage, not a temperature, 273 K is the freezing point of water, and 9000 K would be an unusually blue light.

Why each option is right or wrong
  • (a) 220 is the mains voltage, not a temperature on a tube.
  • (b) 273 K is the freezing point of water.
  • (c) Correct: 6500 K is the daylight colour temperature printed on tubes.
  • (d) 9000 K is not a usual tube rating.

Explanation: written by UPSC Grade, not by UPSC.

Source: UPSC, Civil Services (Preliminary) Examination 2006, General Studies. UPSC's own paper isn't online; the words are from a published compilation. The paper on upsc.gov.in.