Two particles $$X$$ and $$Y$$ having equal charges are being accelerated through the same potential difference. Thereafter they enter normally in a region of uniform magnetic field and describes circular paths of radii $$R_1$$ and $$R_2$$ respectively. The mass ratio of $$X$$ and $$Y$$ is :

A proton moving with a constant velocity passes through a region of space without any change in its velocity. If $$\overrightarrow{\mathrm{E}}$$ and $$\overrightarrow{\mathrm{B}}$$ represent the electric and magnetic fields respectively, then the region of space may have :

(A) $$\mathrm{E}=0, \mathrm{~B}=0$$

(B) $$\mathrm{E}=0, \mathrm{~B} \neq 0$$

(C) $$\mathrm{E} \neq 0, \mathrm{~B}=0$$

(D) $$\mathrm{E} \neq 0, \mathrm{~B} \neq 0$$

Choose the most appropriate answer from the options given below :

An electron is moving along the positive $$\mathrm{x}$$-axis. If the uniform magnetic field is applied parallel to the negative z-axis, then

A. The electron will experience magnetic force along positive y-axis

B. The electron will experience magnetic force along negative y-axis

C. The electron will not experience any force in magnetic field

D. The electron will continue to move along the positive $$\mathrm{x}$$-axis

E. The electron will move along circular path in magnetic field

Choose the correct answer from the options given below:

The source of time varying magnetic field may be

(A) a permanent magnet

(B) an electric field changing linearly with time

(C) direct current

(D) a decelerating charge particle

(E) an antenna fed with a digital signal

Choose the correct answer from the options given below: