Class 11 Physics Chapter 1: Units and Measurement Assertion-reason questions with answers
2 assertion-reason questions on Units and Measurement, each with its answer and the reason, written from the NCERT chapter. For school exams on the CBSE pattern, JEE Main and NEET, which are set from the same NCERT chapter. Open a question's solution to check your working; then take the free test to find your next chapter. Each question gives an Assertion (A) and a Reason (R); choose how they stand to each other.
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Answer: (a) Both A and R are true, and R is the correct explanation of A.
Force [M L T⁻²] and velocity [L T⁻¹] have different dimensions, so by the principle of homogeneity they cannot be added. R is true and is exactly why A is true.
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Answer: (c) A is true, but R is false.
Solid angle is dA/r², a ratio of two areas, so it is dimensionless though it is measured in steradian: A is true. R is false: plane angle and solid angle have units but no dimensions.