NCERT Solutions for Chapter: Moving Charges and Magnetism, Exercise 1: MCQ

Two charged particles traverse identical helical paths in a completely opposite sense in a uniform magnetic field $B=B_{\circ } \hat{\mathrm{k}}$ .

Biot-Savart law indicates that the moving electrons (velocity $v$) produce a magnetic field $\mathrm{B}$ such that

A current carrying circular loop of radius $R$ is placed in the $x-y$ plane with centre at the origin. Half of the loop with $x>0$ is now bent so that it now lies in the $y-z$ plane.
 

An electron is projected with uniform velocity along the axis of a current carrying long solenoid. Which of the following is true?

In a cyclotron, a charged particle

A circular current loop of magnetic moment $M$ is in an arbitrary orientation in an external magnetic field $B$. The work done to rotate the loop by $30°$ about an axis perpendicular to its plane is