Units & Measurements
Practice Questions
MCQ (Single Correct Answer)
1

The velocity of a particle (v) at an instant t is given by $$v = at + b{t^2}$$ the dimension of b is

WB JEE 2008
2

A quantity $X$ is given by $\varepsilon_0 L \frac{\Delta V}{\Delta t}$, where $\varepsilon_0$ is the permittivity of free space, $L$ is the length, $\Delta V$ is a potential difference and $\Delta t$ is a time interval. The dimension of $X$ is same as that of

WB JEE 2025
3

The resistance $\mathrm{R}=\frac{\mathrm{V}}{\mathrm{I}}$ where $\mathrm{V}=(25 \pm 0.4)$ Volt and $\mathrm{I}=(200 \pm 3)$ Ampere. The percentage error in ' $R$ ' is

WB JEE 2025
4

The Power $$(\mathrm{P})$$ radiated from an accelerated charged particle is given by $$\mathrm{P} \propto \frac{(q \mathrm{a})^{\mathrm{m}}}{\mathrm{c}^{\mathrm{n}}}$$ where $$\mathrm{q}$$ is the charge, $$\mathrm{a}$$ is the acceleration of the particle and $$\mathrm{c}$$ is speed of light in vacuum. From dimensional analysis, the value of $$m$$ and $$n$$ respectively, are

WB JEE 2024
5

Which of the following quantity has the dimension of length ?

(h is Planck's constant, m is the mass of electron and c is the velocity of light)

WB JEE 2024
6

In an experiment, the length of an object is measured to be 6.50 cm. This measured value can be written as 0.0650 m. The number of significant figures on 0.0650 m is

WB JEE 2023
7

A modified gravitational potential is given by $$\mathrm{V}=-\frac{\mathrm{GM}}{\mathrm{r}}+\frac{\mathrm{A}}{\mathrm{r}^{2}}$$. If the constant A is expressed in terms of gravitational constant (G), mass (M) and velocity of light (c), then from dimensional analysis, A is,

WB JEE 2023
8

Given : The percentage error in the measurements of A, B, C and D are respectively, 4%, 2%, 3% and 1%. The relative error in $$Z = {{{A^4}{B^{{1 \over 3}}}} \over {C{D^{{3 \over 2}}}}}$$ is

WB JEE 2022
9

The Entropy (S) of a black hole can be written as $$S = \beta {k_B}A$$, where kB is the Boltzmann constant and A is the area of the black hole. The $$\beta$$ has dimension of

WB JEE 2022
10
From dimensional analysis, the Rydberg constant can be expressed in terms of electric charge (e), mass (m) and Planck constant (h) as [consider $${1 \over {4\pi {\varepsilon _0}}} \equiv 1$$ unit]
WB JEE 2021
11
The frequency v of the radiation emitted by an atom when an electron jumps from one orbit to another is given by v = k$$\delta $$E, where k is a constant and $$\delta $$E is the change in energy level due to the transition. Then, dimension of k is
WB JEE 2020
12
The correct dimensional formula for impulse is given by
WB JEE 2019
13
The density of the material of a cube can be estimated by measuring its mass and the length of one of its sides. If the maximum error in the measurement of mass and length are 0.3% and 0.2% respectively, the maximum error in the estimation of the density of the cube is approximately
WB JEE 2019
14
A spherical liquid drop is placed on a horizontal plane. A small distance causes the volume of the drop to oscillate. The time period of oscillation (T) of the liquid drop depends on radius (r) of the drop, density ($$\rho $$) and surface tension (S) of th liquid. Which among the following will be a possible expression for T (where, k is a dimensionless constant)?
WB JEE 2018
15
The dimension of the universal constant of gravitation, G is
WB JEE 2017
16
If x = at + bt2, where x is in metre (m) and t is in hour (h), then unit of b will be
WB JEE 2016