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, $[E]$ and $[B]$ stand for dimensions of electric and magnetic fields respectively, while $\left[\epsilon_{0}\right]$ and $\left[\mu_{0}\right]$ stand for dimensions of the permittivity and permeability of free space respectively. $[L]$ and $[T]$ are dimensions of length and time respectively. All the quantities are given in SI units. The relation between $[E]$ and $[B]$ is

JEE Advanced · 2018 · 20 May 2018 · Paper 1 · Units & Measurement

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,

[E]

and

[B]

stand for dimensions of electric and magnetic fields respectively, while

[ϵ_{0}]

and

[μ_{0}]

stand for dimensions of the permittivity and permeability of free space respectively.

[L]

and

[T]

are dimensions of length and time respectively. All the quantities are given in SI units.

[E]

and

[B]

stand for dimensions of electric and magnetic fields respectively, while

[ϵ_{0}]

and

[μ_{0}]

stand for dimensions of the permittivity and permeability of free space respectively.

[L]

and

[T]

are dimensions of length and time respectively. All the quantities are given in SI units.

The relation between

[E]

and

[B]

(A) $[E] = [B] [L] [T]$
(B) $[E] = [B] [L]^{- 1} [T]$
(C) $[E] = [B] [L] [T]^{- 1}$ ✓ Correct
(D) $[E] = [B] [L]^{- 1} [T]^{- 1}$

Answer: (C)

Solution

From

F = q v B

and

E = F / q

, we get

E = v B

. In dimensions:

[E] = [v] [B] = [L T^{- 1}] [B] = [B] [L] [T]^{- 1}

JEE Advanced · 2018 · 20 May 2018 · Paper 1 · Single correct option

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JEE Advanced · 2018 · 20 May 2018 · Paper 1 · Units & Measurement

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