CBSE Class 11 Science Physics · Ch 1: Units and Measurement

Topics in this test

Difficulty: 3 easy · 9 medium · 18 hard

Sample questions with answers

The first 5 questions of this free test.

1. Q1. Which of the following physical quantities has dimensions different from the other three (the odd one out)?

   • A. power
   • B. work
   • C. torque
   • D. kinetic energy
   Solution

   Work, torque and kinetic energy all have dimensions $[ML^2T^{-2}]$, whereas power has dimensions $[ML^2T^{-3}]$.

2. Q2. Consider the following statements about significant figures: (i) All non-zero digits are significant. (ii) Trailing zeros in a number without a decimal point are always significant. (iii) Zeros between two non-zero digits are significant. (iv) The number of significant figures depends on the choice of unit. Which statements are correct?

   • A. (ii) and (iv)
   • B. (i) and (ii)
   • C. (i), (iii) and (iv)
   • D. (i) and (iii)
   Solution

   Non-zero digits and zeros between non-zero digits are always significant, while trailing zeros without a decimal point are ambiguous, and significant figures do not change with the unit used.

3. Q3. Assertion (A): A dimensionally correct equation may still be physically incorrect. Reason (R): Dimensional analysis cannot determine dimensionless constants or decide whether a term is to be added or multiplied. Choose the correct option.

   • A. A is false, but R is true
   • B. A is true, but R is false
   • C. Both A and R are true, but R is not the correct explanation of A
   • D. Both A and R are true, and R is the correct explanation of A
   Solution

   Both statements are true, and the inability of dimensional analysis to fix numerical constants is exactly why a dimensionally correct equation can still be wrong, so R correctly explains A.

4. Q4. The product of two measured lengths $3.8$ m and $2.1$ m, rounded off to the correct number of significant figures, should be reported as

   • A. $7.9$ m
   • B. $7.98$ m
   • C. $8.0$ m
   • D. $8$ m
   Solution

   The product is $7.98$, but each factor has only 2 significant figures, so the result must be rounded to 2 significant figures, giving $8.0$ m.

5. Q5. The relative error in the measurement of the radius of a sphere is $2\%$. The percentage error in the calculated volume of the sphere is

   • A. $0.67\%$
   • B. $2\%$
   • C. $8\%$
   • D. $6\%$
   Solution

   Since $V \propto r^3$, the percentage error in volume is $3$ times that in radius, i.e. $3\times 2\% = 6\%$.

Frequently asked questions

More tests in the CBSE Class 11 Science Test Series 2027 — Chapter-wise + Full Tests

• Biology · Ch 1: The Living WorldFree
• Chemistry · Ch 1: Some Basic Concepts of ChemistryFree
• English · Ch 1: The Portrait of a LadyFree
• Mathematics · Ch 1: SetsFree
• CBSE Class 11 Science Test Series 2027 — Chapter-wise + Full Tests — Full Test
• CBSE Class 11 Science Test Series 2027 — Chapter-wise + Full Tests — Full Test 2
• CBSE Class 11 Science Test Series 2027 — Chapter-wise + Full Tests — Full Test 3
• CBSE Class 11 Science Test Series 2027 — Chapter-wise + Full Tests — Full Test 4
• CBSE Class 11 Science Test Series 2027 — Chapter-wise + Full Tests — Full Test 5

See the full CBSE Class 11 Science Test Series 2027 — Chapter-wise + Full Tests → · CBSE Class 11 Science: pattern, notification & syllabus →