Moving Charges ...

Two particles having same charge and $$KE$$ enter at right angles into the same magnetic field and travel in circular paths of radii $$2 cm$$ and $$3 cm$$ respectively. The ratio of their masses is :

Two long straight parallel wires separated by a distance, carrying equal currents exert a force F per unit length on each other. If the distance of separation is doubled, and the current in each is halved, the force per unit length, between them will be :

A proton of energy $$2 MeV$$ is moving perpendicular to uniform magnetic field of $$2.5 T$$. The force on the proton is : ($$M_p=1.6\times 10^{-27}kg$$ and $$q_{p}=e=1.6\times 10^{-19}C$$ ) 

A proton of energy $$E$$ is moving along a circular path in a uniform magnetic field. If an alpha particle describes the same circular path, its energy should be :

An electron travelling with a velocity $$\bar{V}=10^{7}i\ m/s$$ enter a magnetic field of induction $$\bar{B}=\overline{2j}$$ . The force on electron is 

Electrons accelerated by a potential difference $$V$$ enter a uniform magnetic field of flux density $$B$$ at right angles to the field. They describe a circular path of radius $$r$$. If now $$V$$ is doubled and $$B$$ is also doubled, the radius of the new circular path is :

A proton moving with a velocity of $$(6\hat{i} + 8\hat{j}) \times 10^{5} \ ms^{-1}$$ enters uniform magnetic field of induction $$5 \times 10^{-3} \hat{k}T$$ . The magnitude of the force acting on the proton is :
($$\hat{i}, \hat{j}$$ and $$\hat{k}$$ are unit vectors forming a right handed triad)

If a particle of charge $$10^{-12}C$$  moving along the x-axis with a velocity $$10^{5}$$ m/s. experiences a force of $$10^{-10}N$$ in y-direction due to magnetic field, then the minimum magnetic field is. 

Acceleration experienced by a particle with specific charge $$1 \times10^{7} C/kg$$ when fired perpendicular to a magnetic field of induction $$100 T$$ with a velocity $$10^{5} ms^{-1}$$ is :

An $$\alpha $$ -particle describes a circular path of radius $$r$$ in a magnetic field $$B$$. The radius of the circular path described by the proton of same energy in the same magnetic field is :