In a certain region,static electric and magnetic fields exist. The magnetic field is given by $\vec B = B_0(\hat i + 2\hat j - 4\hat k)$. If a test charge moving with a velocity $\vec v = v_0(3\hat i - \hat j + 2\hat k)$ experiences no force in that region,then the electric field in the region,in $SI$ units,is

The electrostatic force $(\vec{F}_1)$ and magnetic force $(\vec{F}_2)$ acting on a charge $q$ moving with velocity $\vec{v}$ can be written as:

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 $(2)$.

$A$ particle of charge $2 \ C$ is moving with a velocity of $(3 \hat{i} + 4 \hat{j}) \ ms^{-1}$ in the presence of magnetic and electric fields. If the magnetic field is $(\hat{i} + 2 \hat{j} + 3 \hat{k}) \ T$ and the electric field is $(-2 \hat{k}) \ NC^{-1}$,then the Lorentz force on the particle is: (in $N$)

Write the equation for the Lorentz force.

Give the definition of magnetic field and provide its unit.