An electron enters a region where magnetic $(B)$ and electric $(E)$ fields are mutually perpendicular to one another,then

An electron is moving with a velocity $\vec{v} = (2 \hat{i} + 3 \hat{j}) \text{ m/s}$ in an electric field $\vec{E} = (3 \hat{i} + 6 \hat{j} + 2 \hat{k}) \text{ V/m}$ and a magnetic field $\vec{B} = (2 \hat{j} + 3 \hat{k}) \text{ T}$. Calculate the magnitude and direction (with $x$-axis) of the Lorentz force acting on the electron.

$A$ particle having charge $10^{-9} \text{ C}$ moving in the $x-y$ plane in fields of $0.4 \hat{i} \text{ N/C}$ and $4 \times 10^{-3} \hat{k} \text{ T}$ experiences a force of $(4 \hat{i} + 2 \hat{j}) \times 10^{-10} \text{ N}$. The velocity of the particle at that instant is . . . . . . $\text{m/s}$.

$A$ charged particle carrying charge $1\,\mu C$ is moving with velocity $(2 \hat{i} + 3 \hat{j} + 4 \hat{k})\, ms^{-1}$. If an external magnetic field of $(5 \hat{i} + 3 \hat{j} - 6 \hat{k}) \times 10^{-3}\, T$ exists in the region where the particle is moving,then the force on the particle is $\overrightarrow{F} \times 10^{-9}\, N$. The vector $\overrightarrow{F}$ is:

In electromagnetic theory, electric and magnetic phenomena are related to each other. Therefore, the dimensions of electric and magnetic quantities must also be related. In the questions below, $[E]$ and $[B]$ stand for dimensions of electric and magnetic fields respectively, while $[\varepsilon_0]$ and $[\mu_0]$ stand for dimensions of the permittivity and permeability of free space respectively. $L$ and $T$ are dimensions of length and time respectively. All quantities are in $SI$ units.
$(1)$ The relation between $[E]$ and $[B]$ is:
$(A)$ $[E]=[B][L][T]^{-1}$
$(B)$ $[E]=[B][L][T]$
$(C)$ $[E]=[B][L]^{-1}[T]$
$(D)$ $[E]=[B][L]^{-1}[T]^{-1}$
$(2)$ The relation between $[\varepsilon_0]$ and $[\mu_0]$ is:
$(A)$ $[\mu_0]=[\varepsilon_0][L]^2[T]^{-2}$
$(B)$ $[\mu_0]=[\varepsilon_0]^{-1}[L]^{-2}[T]^2$
$(C)$ $[\mu_0]=[\varepsilon_0][L]^{-2}[T]^2$
$(D)$ $[\mu_0]=[\varepsilon_0]^{-1}[L]^2[T]^{-2}$
Select the correct options for $(1)$ and $(2)$.

If a charged particle moves unaccelerated through a region containing both electric and magnetic fields,which of the following must be true?