Question 1

Which of the following is not a fundamental unit?

Accepted Answer

Ampere, metre, and kilogram are fundamental units in the SI system, whereas newton is a derived unit of force.

Question 2

Light year is a unit of:

Accepted Answer

Light year is the distance travelled by light in a vacuum in one year. Therefore, it is a unit of distance.

Question 3

Dimensional formula for Planck's constant is:

Accepted Answer

Energy E = h nu, so h = E / nu. Dimensional formula of energy is ML^2T^-2 and frequency is T^-1. Thus, ML^2T^-1.

Question 4

The number of significant figures in 0.007 is:

Accepted Answer

Trailing zeros to the left of the first non-zero digit are not significant. Only the digit 7 is significant here.

Question 5

Which of the following pairs has the same dimensions?

Accepted Answer

Work and torque both have the dimensional formula ML^2T^-2.

Units and Measurements — CBSE Class 11 Physics Important Questions & Revision Notes