Question

The dimensional formula of electric charge is
1. [M⁰ L⁰ T¹ A¹]
2. [M¹ L⁰ T² A^-1]
3. [M⁰ L⁰ T¹]
4. [M⁰ L⁰ T⁰ A¹]

Answer 1

Correct Answer - Option 1 : [M⁰ L⁰ T¹ A¹]

The correct answer is option 1) i.e. [M0 L0 T1 A1]

CONCEPT:

• The dimensional formula is used to express any physical quantity in terms of fundamental quantities.
• Fundamental quantity: A quantity that can be measured is called a physical quantity. 
  • Fundamental quantities are those which cannot be expressed or measured in terms of other physical quantities. 
  • The SI system has seven fundamental quantities i.e. time, length, mass, electric current, thermodynamic temperature, amount of substance, and luminous intensity. 

The seven fundamental quantities along with their dimensions are as follows:

Fundamental quantity	Dimension
Time	T
Mass	M
Electric current	A
Thermodynamic temperature	K
Amount of substance	mol
Luminous intensity	cd
Length	L

• Electric current is defined as the charge flowing per unit time.

It is given by:

\(I = \frac{q}{t}\)

Where I is current, q is the charge and t is the time.

EXPLANATION:

• The dimension of electric current is [A] and that of time is [T].

We know, \(I = \frac{q}{t}\) ⇒ q = I × t = [A¹ T¹]

• Thus, the dimensional formula of electric charge q is [M0 L0 T1 A1]