NEET Physics Dimensions of Physical Quantities MCQs Set A

Question. Dimensional analysis can be applied to
(a) All of these
(b) to convert from one system of units to another
(c) deduce relations among the physical quantities
(d) check the dimensional consistency of equations

Answer: A

Question. The dimensional formula for relative density is
(a) [M^oL^oT^o]
(b) [M^oL^–3]
(c) [ML^–3]
(d) None of these

Answer: A

Question. The dimensions of speed and velocity are
(a) [LT^–1], [LT ^–1]
(b) [LT^–1], [LT ^–2]
(c) [L²T], [LT ^–1]
(d) [LT], [LT]

Answer: A

Question.  [MLT^–1] + [MLT^–1] = .............
(a) [MLT^–1]
(b) None of these
(c) [M°L°T°]
(d) 2[MLT^–1]

Answer: A

Question. The dimensions of pressure is equal to
(a) energy per unit volume
(b) energy
(c) force per unit volume
(d) force

Answer: A

Question. The physical quantity that has no dimensions is
(a) strain
(b) angular momentum
(c) angular velocity
(d) linear momentum

Answer: A

Question. Which is dimensionless?
(a) Energy/work
(b) Velocity/acceleration
(c) Force/acceleration
(d) Volume/area

Answer: A

Question. The division of energy by time is X. The dimensional formula of X is same as that of
(a) power
(b) electric field
(c) momentum
(d) torque

Answer: A

Question. Which of the following is a dimensional constant?
(a) Gravitational constant
(b) Dielectric constant
(c) Refractive index
(d) Relative density

Answer: A

Question. The ratio of the dimensions of Planck’s constant and that of the moment of inertia is the dimensions of
(a) frequency
(b) time
(c) velocity
(d) angular momentum

Answer: A

Question. Two quantities A and B have same dimensions which mathematical operation given below is physically meaningful?
(a) A/B
(b) A + B²
(c) A² – B
(d) A = B²

Answer: A

Question. If P,Q, R are physical quantities, having different dimensions, which of the following combinations can never be a meaningful quantity?
(a) (P – Q) / R
(b) PQ / R
(c) PQ – R
(d) (PR – Q²) / R

Answer: A

Question. If the dimensions of a physical quantity are given by M^a L^b T^c, then the physical quantity will be
(a) pressure if a = 1, b = – 1, c = – 2
(b) force if a = 0, b = – 1, c = – 2
(c) acceleration if a = 1, b = 1, c = – 2
(d) velocity if a = 1, b = 0, c = – 1

Answer: A

Question. A force is given by F = at + bt², where t is time, the dimensions of a and b are
(a) [M L T^–3] and [M L T^–4]
(b) [M L T^–3] and [M L T⁰]
(c) [M L T^–1] and [M L T⁰]
(d) [M L T^–4] and [M L T^–1]

Answer: A

Question. The thrust developed by a rocket-motor is given by F = mv + A(P₁ – P₂) where m is the mass of the gas ejected per unit time, v is velocity of the gas, A is area of cross-section of the nozzle, P₁ and P₂ are the pressures of the exhaust gas and surrounding atmosphere. The formula is dimensionally
(a) correct
(b) wrong
(c) sometimes wrong, sometimes correct
(d) Data is not adequate

Answer: A