CBSE Class 12 · 2008 · Magnetic Effects of CurrentVery Short Answer

(i) State and explain Ampere's circuital law.
(ii) Two long straight parallel wires separated by $20\text{cm}$ carry $5\text{A}$ and $10\text{A}$ current respectively in the same direction. Find the magnitude and direction of the net magnetic field at a point midway between …

Assertion (A): The energy of a charged particle moving in a magnetic field does not change.
Reason (R): It is because the work done by the magnetic force on the charge moving in a magnetic field is zero.

Derive an expression for the magnetic force $\vec{F}$ acting on a straight conductor of length $L$ carrying current $I$ in an external magnetic field $\vec{B}$. Is it valid when the conductor is in zig-zag form? Justify.

An electron moving with a velocity $\vec{v}=(1.0\times 10^7\text{m/s})\hat{i}+(0.5\times 10^7\text{m/s})\hat{j}$ enters a region of uniform magnetic field $\vec{B}=(0.5\text{mT})\hat{j}$. Find the radius of the circular path described by it. While rotating, does …

Beams of electrons and protons move parallel to each other in the same direction. They

A long straight wire of radius $a$ carries a steady current $I$ distributed uniformly across its cross-section. The ratio of the magnitudes of the magnetic field ${\vec{B}}_1$ at $\frac{a}{2}$ and ${\vec{B}}_2$ at a distance $2a$ from the axis is