A. [ML2T-3A-1]
B. [ML2T-3A-2]
C. [MLT-3A-1]
D. [M0L0T0A0]
Answer: The correct dimensional formula for the electric field is [MLT⁻³A⁻¹].
An electric field is a region around a charged particle or object where a force is exerted on other charges. The electric field is represented by the symbol E, and its SI unit is newtons per coulomb (N/C) or volts per meter (V/m). It is a fundamental concept in electromagnetism and plays a critical role in understanding forces between charges. To understand the dimensional formula for the electric field, let’s break it down step by step:
Complete Answer:
What is the Electric Field?
The electric field at a point is defined as the force (F) experienced by a unit positive charge (q) placed at that point. Mathematically:
E is the electric field.
F is the force.
q is the charge.
Now, the formula for force is given by Newton’s second law:
F = ma
where m is mass and a is acceleration. The dimensional formula for F is [MLT⁻²].
The dimensional formula for charge (q) is derived from the relationship:
q = I ⋅ t
where 𝐼 is current, and 𝑡 is time. The dimensional formula for 𝑞 is [AT].
Substituting these into the electric field formula:
Evaluating the Options
Let’s match this calculation with the options:
Option A: [ML²T⁻³A⁻¹]
Incorrect. The exponent for L is 2, which doesn’t align with the formula derived above.
Option B: [ML²T⁻³A⁻²]
Incorrect. The charge exponent A-2 is incorrect here.
Option C: [MLT⁻³A⁻¹]
Correct. This matches the derived dimensional formula for the electric field.
Option D: [M⁰L⁰T⁰A⁰]
Incorrect. This represents a dimensionless quantity, which is not applicable to the electric field.
Additional Insights on Electric Field
Here is some more information about the electric field you should know for a clearer concept:
Types of Electric Fields:
- Uniform Electric Field: Same magnitude and direction everywhere (e.g., between parallel capacitor plates).
- Non-Uniform Electric Field: Varies in magnitude and/or direction (e.g., around a point charge).
Practical Applications: Electric fields are used in capacitors, cathode ray tubes, and even in modern-day devices like touchscreens.
Fun Fact: The concept of an electric field was first introduced by Michael Faraday in the 19th century to describe forces between charges without physical contact.
Common Doubts in Physics