Class 11 Physics MCQ – Dimensional Formulae and Equations

This set of Class 11 Physics Chapter 2 Multiple Choice Questions & Answers (MCQs) focuses on “Dimensional Formulae and Equations”.

1. [MLT-2] matches with the dimensional formula of ____
a) Force
b) Modulus of elasticity
c) Displacement
d) Strain
View Answer

Answer: a
Explanation: The given dimensional formula matches with that of force. Force = mass x acceleration.

2. What is the maximum number of unknowns that can be found through a simple dimensional equation?
a) 6
b) 5
c) 3
d) 2
View Answer

Answer: c
Explanation: A simple dimensional equation uses three basic parameters – mass, length and time. Hence the maximum number of unknowns that can be found is 3.

3. If, v stands for velocity, L for length, T for time and M for mass, what is the value of x in the equation –
L = (vT/M)x?
a) 3
b) 2
c) 1
d) 0
View Answer

Answer: d
Explanation: The dimensions of velocity are LT-1. The dimensions of the RHS are LM-x and that of LHS is L. hence on equating we get x = 0.

4. Assuming standard notations, which of the following quantities is dimensionless?
a) v/a
b) P/Fv
c) FE/L
d) V2/g
View Answer

Answer: b
Explanation: P/Fv is a dimensionless quantity. This is because, power(P) = Force(F) x Instantaneous Velocity(v).

5. If the units of length and time are doubled, what will be the factor by which the unit of acceleration will change?
a) 1
b) 0.25
c) 0.5
d) 2
View Answer

Answer: c
Explanation: The dimensions of acceleration are LT-2. On doubling both length and time, the new dimensions become (0.5)*LT-2.
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6. What are the dimensions of a light year?
a) L
b) T
c) LT-1
d) M
View Answer

Answer: a
Explanation: Lightyear is the unit of measurement of distance; hence it has the dimensions of distance. Lightyear is the distance travelled by light in one year. It finds its use mostly in astronomy.

7. What are the dimensions of coefficient of friction?
a) MLT-2
b) LT-1
c) L
d) It is dimensionless
View Answer

Answer: d
Explanation: Coefficient of friction is the ratio of Frictional force to Normal Reaction force; hence it is dimensionless. The formula for calculating this is, f = µN.

Sanfoundry Global Education & Learning Series – Physics – Class 11.

To practice all chapters and topics of class 11 Physics, here is complete set of 1000+ Multiple Choice Questions and Answers.


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