In velocity selector device, the electric field and the magnetic fields are present as perpendicular to each other. What is the velocity of the charged particle moving under the influence of electric field of $3.78\times {10}^3 \mathrm{N} {\mathrm{C}}^{-1}$ and magnetic field of $0.363 \mathrm{T}$?

At a place, an electric field and a magnetic field are in the downward direction. There an electron moves in the downward direction. Hence this electron.____________.

In a region, an electric field $\overrightarrow{E}=5x^3 \hat{j} {\mathrm{NC}}^{-1}$ and a magnetic field of $\overrightarrow{B}=0.1 \hat{k} \mathrm{T}$ are applied. A beam of positively charged particles is projected along X-direction. Find the velocity of particles that move undeflected in these crossed fields.

A velocity selector consists of electric field $\overrightarrow{E}=E \hat{\mathrm{k}}$ and magnetic field $\overrightarrow{B}=B \hat{\mathrm{j}}$ with $B=12 \mathrm{mT}$. The value $E$ required for an electron of energy $728\mathrm{eV}$ moving along the positive $\mathrm{x}$-axis to pass undeflected is 

(Given, mass of electron $=9.1\times {10}^{-31} \mathrm{kg}$)

Explain how crossed $\overrightarrow{E}$ and $\overrightarrow{B}$ fields serve as a velocity selector.

A particle a mass of ${10}^{-2} \mathrm{kg}$ carries a charge of $5\times {10}^{-8}\mathrm{C}$. The particle is given an initial horizontal velocity of ${10}^5{ \mathrm{ms}}_{}^{-1}$ in the presence of electric field $\overrightarrow{E}$ and magnetic field $\overrightarrow{\mathrm{B}}$. To keep the particle moving in a horizontal direction, it is necessary that

(i) $\overrightarrow{B}$ should be perpendicular, to the direction of velocity and $\overrightarrow{E}$ should be along the direction of velocity.

(ii) Both $\overrightarrow{B}$ and $\overrightarrow{E}$ should be along the direction of velocity.

(iii) Both $\overrightarrow{B}$ and $\overrightarrow{E}$ are mutually perpendicular and perpendicular to the direction of velocity.

(iv) $\overrightarrow{B}$ should be along the direction of velocity and $\overrightarrow{E}$ should be perpendicular to the direction of velocity.

Which one of the following pairs of statements is possible?

Twelve wires of equal lengths are connected in the form of a skeleton-cube which is moving with a velocity $\overrightarrow{v}$ in the direction of a magnetic field $\overrightarrow{B}$. Find the emf in each arm of the cube.

Two similar bars $P$ and $Q$ 'made from different materials', are introduced in two identical uniform magnetic fields. The figures given below show the re-distribution of magnetic lines of force. Which of these materials is paramagnetic and why?