An electron and a proton having the same momenta enter perpendicularly into a magnetic field. What are their trajectories in the field?

A particle having a charge $$100 \mathrm{e}$$ is revolving in a circular path of radius $$0.8 \mathrm{~m}$$ with 1. r.p.s The magnetic field produced at the centre of the circle in SI unit is $$\left(\mu_0=\right.$$ permeability of vacuum, $$e= \left.1.6 \times 10^{-19} \mathrm{C}\right)$$

The magnetic field inside a current carrying toroidal solenoid is $$0.2 \mathrm{~mT}$$. What is the magnetic field inside the toroid if the current through it is tripled and radius is made $$\frac{1}{3}^{\text {rd}}$$ ?

A, B and C are three parallel conductors of equal lengths carrying currents $$\mathrm{I}, \mathrm{I}$$ and $$2 \mathrm{I}$$ respectively. Distance between A and B is '$$x$$' and that between B and C is also '$$x$$'. $$F_1$$ is the force exerted by conductor $$\mathrm{B}$$ on $$\mathrm{A}$$. $$\mathrm{F}_2$$ is the force exerted by conductor $$\mathrm{C}$$ on $$\mathrm{A}$$. Current $$\mathrm{I}$$ in $$\mathrm{A}$$ and $$\mathrm{I}$$ in $$\mathrm{B}$$ are in same direction and current $$2 \mathrm{I}$$ in $$\mathrm{C}$$ is in opposite direction. Then