Question

Which of the following is not a unit of time?

1. Second
2. Parsec
3. Year
4. Light year

Answer 1

b. Parsec

d. Light year

Explanation:

Parsec and light year are those practical units which are used to measure large distances. For example, the distance between the sun and earth or other celestial bodies. So they are the units of length, not time. Here, the second and year represent time.

Important point: 1 light year (distance that light travels in 1 year with speed = 3 × 10⁸ m/s.) = 9.46 × 10¹¹ m And 1 par see = 3.08 × 10¹⁶ m.