A conductor of length $l$ and mass $m$ is placed along the east-west line on a table. Suddenly a certain amount of charge is passed through it and it is found to jump to a height $h$. The earth’s magnetic induction is $B$. The charge passed through the conductor is: 

An arrangement of three parallel straight wires placed perpendicular to plane of paper carrying same current $'I'$ along the same direction as shown in figure. Magnitude of force per unit length on the middle wire $'B'$ is given by 

A charge of $4.0 \mu \mathrm{C}$ is moving with a velocity of $4.0 \times 10^6 \mathrm{~ms}^{-1}$ along the positive $\mathrm{y}$-axis under a magnetic field $\vec{B}$ of strength $(2 \hat{k})\  T$. The force acting on the charge is $x \hat{i} N$. The value of $x$ is__________.

Define Ampere from two current carrying parallel wires.

A straight current carrying conductor is placed in such a way that the current in the conductor flows in the direction out of the plane of the paper. The conductor is placed between two poles of two magnets, as shown. The conductor will experience a force in the direction towards

Two coaxial solenoids of different radii carry current $I$ in the same direction. Let $\;{\overrightarrow {\;F} _1}$ be the magnetic force on the inner solenoid due to the outer one and $\;{\overrightarrow {\;F} _2}$ be the magnetic force on the outer solenoid due to the inner one. Then