Sigma Percentile
JEE Main 2021
LEVELJEE Main

Animated Solution for Physics - Physics and Measurement: Match List I with List II. \begin{array}{ll} \text{List I} & \text{List II} \\ \text{A. Capacitance, } C & \text{I. } M^1 L^1 T^{-3} A^{-1} \\ \text{B. Permittivity of free space, } \varepsilon_0 & \text{II. } M^{-1} L^{-3} T^4 A^2 \\ \text{C. Permeability of free space, } \mu_0 & \text{III. } M^{-1} L^{-2} T^4 A^2 \\ \text{D. Electric field, } E & \text{IV. } M^1 L^1 T^{-2} A^{-2} \end{array} Choose the correct answer from the options given below.

Select Answer:

Visualized Solution

  • We need to find the dimensional formulas for:
  • , , , and

  • Since , we get

  • From Coulomb's Law:

  • Speed of light in vacuum:

  • Electric force per unit charge:

  • A III
  • B II
  • C IV
  • D I

  • What about the dimensions of Magnetic Field ?
  • Try using !

The Sigma Insight: Dimensional Analysis

Solution Diagram

The Beauty of Dimensional Analysis

Imagine you are an explorer in the vast universe of physics, and your most trusted compass is Dimensional Analysis. It is the ultimate truth-teller, the universal translator that strips away the complexity of any physical quantity and reveals its fundamental DNA: Mass (), Length (), Time (), and Current ().
In this epic problem, we are tasked with decoding four of the most profound quantities in electromagnetism: Capacitance, Permittivity, Permeability, and the Electric Field. Let's break them down one by one.

Decoding Capacitance ()

Capacitance is the ability of a system to store electric charge. Mathematically, it is defined as the charge stored per unit potential difference:
But what is potential ()? Potential is simply the work done per unit charge (). Substituting this into our capacitance equation gives us a much friendlier form:
Now, we just plug in the fundamental dimensions. Charge is current times time, so . Work is force times distance, so .
This perfectly matches option III in our list.

Unveiling Permittivity ()

Permittivity of free space tells us how much resistance a vacuum offers to the formation of an electric field. The easiest way to find its dimensions is to summon Coulomb's Law:
By isolating , we get:
We know the dimensions of force (), charge (), and distance (). Let's substitute them in:
This matches option II.

The Speed of Light Trick for Permeability ()

Permeability of free space is the magnetic counterpart to permittivity. While you could use the Biot-Savart law or Ampere's law to find its dimensions, there is a much more elegant trick. James Clerk Maxwell showed us that the speed of light in a vacuum is intimately connected to these two constants:
Squaring both sides and rearranging for gives:
We already did the hard work of finding . The speed of light is just a velocity, so . Let's plug these in:
Simplifying the denominator and bringing the terms to the numerator yields:
This matches option IV.

The Simplicity of the Electric Field ()

Finally, we arrive at the Electric Field. An electric field is simply the electrostatic force experienced per unit charge:
This is the most straightforward calculation of the bunch. We divide the dimensions of force by the dimensions of charge:
This matches option I.

Bringing It All Together

By systematically breaking down each complex quantity into fundamental mechanical dimensions, we have successfully decoded the entire matrix:
- A. Capacitance III - B. Permittivity II - C. Permeability IV - D. Electric Field I
This perfectly aligns with the first option provided in the question. Dimensional analysis is not just a tool for solving problems; it is a profound way to see the underlying unity of the physical world.

Similar Questions

JEE Main 2021
LEVELJEE Main

Match List-I with List-II. $\begin{array}{ll} \text{List-I} & \text{List-II} \\ \text{A. Magnetic induction} & \text{1. } [ML^2T^{-2}A^{-1}] \\ \text{B. Magnetic flux} & \text{2. } [ML^{-1}A] \\ \text{C. Magnetic permeability} & \text{3. } [MT^{-2}A^{-1}] \\ \text{D. Magnetisation} & \text{4. } [MLT^{-2}A^{-2}] \end{array}$ Choose the most appropriate answer from the options given below.

(A)
A 2, B 4, C 1, D 3
(B)
A 2, B 1, C 4, D 3
(C)
A 3, B 2, C 4, D 1
(D)
A 3, B 1, C 4, D 2
JEE Advanced 2018
LEVELJEE Main

Comprehension Passage

In electromagnetic theory, the electric and magnetic phenomena are related to each other. Therefore, the dimensions of electric and magnetic quantities must also be related to each other. In the questions below, and stand for dimensions of electric and magnetic fields respectively, while and stand for dimensions of the permittivity and permeability of free space, respectively. and are dimensions of length and time, respectively. All the quantities are given in SI units.
Question 1:

The relation between and is

(A)
(B)
(C)
(D)
LEVELJEE Main

The dimensions of ( : permittivity of free space; : electric field) is

(A)
(B)
(C)
(D)
LEVELJEE Main

Let denote the dimensional formula of the permittivity of the vacuum and that of the permeability of the vacuum. If , , and .

* Multiple Correct Options
(A)
(B)
(C)
(D)
JEE Main 2021
LEVELJEE Main

Match List-I with List-II Choose the correct answer from the options given below.

List-I

(P)
(Planck's constant)
(Q)
(kinetic energy)
(R)
(electric potential)
(S)
(linear momentum)

List-II

(1)
(2)
(3)
(4)
JEE Main 2013
LEVELJEE Main

Let denotes the dimensional formula of the permittivity of vacuum. If , , and , then

(A)
(B)
(C)
(D)
JEE Main 2021
LEVELJEE Main

Match List-I with List-II. Choose the most appropriate answer from the options given below.

(A)
A 2, B 3, C 4, D 1
(B)
A 3, B 2, C 4, D 1
(C)
A 4, B 2, C 1, D 3
(D)
A 3, B 2, C 1, D 4
JEE Advanced 2018
LEVELJEE Main

Comprehension Passage

In electromagnetic theory, the electric and magnetic phenomena are related to each other. Therefore, the dimensions of electric and magnetic quantities must also be related to each other. In the questions below, and stand for dimensions of electric and magnetic fields respectively, while and stand for dimensions of the permittivity and permeability of free space, respectively. and are dimensions of length and time, respectively. All the quantities are given in SI units.
Question 1:

The relation between and is

(A)
(B)
(C)
(D)
JEE Advanced 1993
LEVELJEE Main

Match the physical quantities given in Column I with dimensions expressed in terms of mass (), length (), time (), and charge () given in Column II and write the correct answer against the matched quantity in a tabular form in your answer book.

List-I

(P)
Angular momentum
(Q)
Latent heat
(R)
Torque
(S)
Capacitance
(T)
Inductance
(U)
Resistivity

List-II

(1)
(2)
(3)
(4)
(5)
(6)
JEE Main 2001
LEVELJEE Main

A quantity is given by , where is the permittivity of free space, is a length, is a potential difference and is a time interval. The dimensional formula for is the same as that of

(A)
resistance
(B)
charge
(C)
voltage
(D)
current