Dimensions — NEET Physics MCQs with Solutions
Free NEET Physics Dimensions MCQs with step-by-step solutions (35 questions). Part of Units and Dimensions. Practise online on Prepizo — no login needed.
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Questions with solutions
Q1 — Dimensions · easy · theory
The dimensional formula of velocity is
A. $[MLT^{-1}]$
B. $[L]$
C. $[LT^{-1}]$ ✓ Correct
D. $[LT^{-2}]$
Solution: Velocity = displacement/time = $[L]/[T] = [LT^{-1}]$.
Q2 — Dimensions · medium · theory
The dimensional formula of acceleration is
A. $[LT^{-2}]$ ✓ Correct
B. $[L^2T^{-2}]$
C. $[LT^{-1}]$
D. $[MLT^{-2}]$
Solution: Acceleration = velocity/time = $[LT^{-1}]/[T] = [LT^{-2}]$.
Q3 — Dimensions · medium · theory
The dimensional formula of force is
A. $[ML^{-1}T^{-2}]$
B. $[MLT^{-1}]$
C. $[ML^2T^{-2}]$
D. $[MLT^{-2}]$ ✓ Correct
Solution: Force = mass × acceleration = $[M][LT^{-2}] = [MLT^{-2}]$.
Q4 — Dimensions · easy · theory
The dimensional formula of work (or energy) is
A. $[MLT^{-2}]$
B. $[ML^2T^{-3}]$
C. $[ML^2T^{-2}]$ ✓ Correct
D. $[ML^2T^{-1}]$
Solution: Work = force × distance = $[MLT^{-2}][L] = [ML^2T^{-2}]$.
Q5 — Dimensions · easy · theory
The dimensional formula of power is
A. $[ML^2T^{-2}]$
B. $[ML^2T^{-1}]$
C. $[MLT^{-2}]$
D. $[ML^2T^{-3}]$ ✓ Correct
Solution: Power = work/time = $[ML^2T^{-2}]/[T] = [ML^2T^{-3}]$.
Q6 — Dimensions · easy · theory
The dimensional formula of momentum is
A. $[ML^2T^{-1}]$
B. $[MLT^{-2}]$
C. $[ML^2T^{-2}]$
D. $[MLT^{-1}]$ ✓ Correct
Solution: Momentum = mass × velocity = $[M][LT^{-1}] = [MLT^{-1}]$.
Q7 — Dimensions · easy · theory
The dimensional formula of pressure is
A. $[ML^2T^{-2}]$
B. $[MLT^{-2}]$
C. $[ML^{-2}T^{-2}]$
D. $[ML^{-1}T^{-2}]$ ✓ Correct
Solution: Pressure = force/area = $[MLT^{-2}]/[L^2] = [ML^{-1}T^{-2}]$.
Q8 — Dimensions · easy · theory
The dimensional formula of density is
A. $[ML^{-2}]$
B. $[ML^{3}]$
C. $[ML^{-3}]$ ✓ Correct
D. $[M^{-1}L^3]$
Solution: Density = mass/volume = $[M]/[L^3] = [ML^{-3}]$.
Q9 — Dimensions · medium · theory
The dimensional formula of impulse is
A. $[MLT^{-1}]$ ✓ Correct
B. $[MLT^{-2}]$
C. $[ML^2T^{-2}]$
D. $[ML^2T^{-1}]$
Solution: Impulse = force × time = $[MLT^{-2}][T] = [MLT^{-1}]$ — same as momentum.
Q10 — Dimensions · easy · theory
The dimensional formula of frequency is
A. $[T^{-1}]$ ✓ Correct
B. $[T]$
C. $[T^{-2}]$
D. $[LT^{-1}]$
Solution: Frequency = 1/time = $[T^{-1}]$.
Q11 — Dimensions · easy · theory
The dimensional formula of torque is
A. $[ML^2T^{-2}]$ ✓ Correct
B. $[ML^2T^{-3}]$
C. $[MLT^{-2}]$
D. $[ML^2T^{-1}]$
Solution: Torque = force × distance = $[MLT^{-2}][L] = [ML^2T^{-2}]$ — same as energy.
Q12 — Dimensions · easy · theory
The dimensional formula of angular momentum is
A. $[ML^2T^{-3}]$
B. $[MLT^{-1}]$
C. $[ML^2T^{-1}]$ ✓ Correct
D. $[ML^2T^{-2}]$
Solution: Angular momentum = r × p = $[L][MLT^{-1}] = [ML^2T^{-1}]$.
Q13 — Dimensions · medium · theory
The dimensional formula of the universal gravitational constant $G$ is
A. $[M^{-1}L^3T^{-2}]$ ✓ Correct
B. $[M^{-1}L^2T^{-2}]$
C. $[ML^3T^{-2}]$
D. $[MLT^{-2}]$
Solution: From $F = \frac{Gm_1m_2}{r^2}$, $G = \frac{Fr^2}{m^2} = \frac{[MLT^{-2}][L^2]}{[M^2]} = [M^{-1}L^3T^{-2}]$.
Q14 — Dimensions · medium · theory
The dimensional formula of Planck's constant $h$ is
A. $[ML^2T^{-1}]$ ✓ Correct
B. $[ML^2T^{-3}]$
C. $[MLT^{-1}]$
D. $[ML^2T^{-2}]$
Solution: From $E = h\nu$, $h = E/\nu = [ML^2T^{-2}]/[T^{-1}] = [ML^2T^{-1}]$ — same as angular momentum.
Q15 — Dimensions · medium · theory
The dimensional formula of the coefficient of viscosity is
A. $[ML^{-2}T^{-1}]$
B. $[MLT^{-1}]$
C. $[ML^{-1}T^{-1}]$ ✓ Correct
D. $[ML^{-1}T^{-2}]$
Solution: The coefficient of viscosity has dimensions $[ML^{-1}T^{-1}]$ (SI unit: poiseuille or Pa·s).
Q16 — Dimensions · easy · theory
The dimensional formula of surface tension is
A. $[MT^{-2}]$ ✓ Correct
B. $[ML^{-1}T^{-2}]$
C. $[MT^{-1}]$
D. $[MLT^{-2}]$
Solution: Surface tension = force/length = $[MLT^{-2}]/[L] = [MT^{-2}]$.
Q17 — Dimensions · medium · theory
The dimensional formula of Young's modulus is
A. $[ML^{-1}T^{-2}]$ ✓ Correct
B. $[MT^{-2}]$
C. $[ML^2T^{-2}]$
D. $[MLT^{-2}]$
Solution: Young's modulus = stress/strain; strain is dimensionless, so it equals the dimensions of pressure, $[ML^{-1}T^{-2}]$.
Q18 — Dimensions · easy · theory
Which pair has the SAME dimensional formula?
A. Velocity and acceleration
B. Work and torque ✓ Correct
C. Force and power
D. Momentum and energy
Solution: Both work and torque have dimensions $[ML^2T^{-2}]$.
Q19 — Dimensions · medium · theory
Which pair has the SAME dimensions?
A. Pressure and force
B. Impulse and momentum ✓ Correct
C. Energy and power
D. Force and work
Solution: Impulse and momentum both have dimensions $[MLT^{-1}]$.
Q20 — Dimensions · medium · theory
Which physical quantity is dimensionless?
A. Density
B. Velocity
C. Force
D. Strain ✓ Correct
Solution: Strain is a ratio of two lengths, so it has no dimensions.
Q21 — Dimensions · easy · theory
The dimensional formula of area is
A. $[ML^2]$
B. $[L^2]$ ✓ Correct
C. $[L^3]$
D. $[L]$
Solution: Area = length × length = $[L^2]$.
Q22 — Dimensions · easy · theory
The dimensional formula of volume is
A. $[ML^3]$
B. $[L^2]$
C. $[L^3]$ ✓ Correct
D. $[L]$
Solution: Volume = length³ = $[L^3]$.
Q23 — Dimensions · easy · theory
The dimensional formula of angle (in radians) is
A. $[L]$
B. $[T^{-1}]$
C. $[LT^{-1}]$
D. Dimensionless $[M^0L^0T^0]$ ✓ Correct
Solution: Angle = arc/radius = $[L]/[L]$, so it is dimensionless.
Q24 — Dimensions · easy · theory
The dimensional formula of angular velocity is
A. $[T^{-2}]$
B. $[T^{-1}]$ ✓ Correct
C. $[LT^{-1}]$
D. $[LT^{-2}]$
Solution: Angular velocity = angle/time = (dimensionless)/$[T] = [T^{-1}]$.
Q25 — Dimensions · medium · theory
The dimensional formula of the gravitational field (acceleration due to gravity, $g$) is
A. $[LT^{-1}]$
B. $[LT^{-2}]$ ✓ Correct
C. $[MLT^{-2}]$
D. $[T^{-2}]$
Solution: g is an acceleration, so its dimensions are $[LT^{-2}]$.
Q26 — Dimensions · easy · theory
The dimensional formula of kinetic energy is
A. $[ML^2T^{-1}]$
B. $[ML^2T^{-2}]$ ✓ Correct
C. $[MLT^{-2}]$
D. $[MLT^{-1}]$
Solution: KE = ½mv² = $[M][LT^{-1}]^2 = [ML^2T^{-2}]$.
Q27 — Dimensions · easy · theory
The dimensional formula of the spring constant $k$ (from $F = kx$) is
A. $[MLT^{-2}]$
B. $[MT^{-2}]$ ✓ Correct
C. $[ML T^{-2}]$
D. $[MT^{-1}]$
Solution: k = F/x = $[MLT^{-2}]/[L] = [MT^{-2}]$.
Q28 — Dimensions · easy · theory
The dimensional formula of stress is
A. $[ML^{-1}T^{-2}]$ ✓ Correct
B. $[MLT^{-2}]$
C. $[MT^{-2}]$
D. $[ML^2T^{-2}]$
Solution: Stress = force/area = $[MLT^{-2}]/[L^2] = [ML^{-1}T^{-2}]$ — same as pressure.
Q29 — Dimensions · easy · theory
The dimensional formula of gravitational potential energy $mgh$ is
A. $[ML^2T^{-1}]$
B. $[MgL]$
C. $[ML^2T^{-2}]$ ✓ Correct
D. $[MLT^{-2}]$
Solution: $mgh = [M][LT^{-2}][L] = [ML^2T^{-2}]$ — the dimensions of energy.
Q30 — Dimensions · medium · theory
Two quantities can be added only if they have
A. The same magnitude
B. The same dimensions ✓ Correct
C. Opposite signs
D. The same units always
Solution: By the principle of homogeneity, only quantities with identical dimensions can be added or subtracted.