Question

Four charged objects are placed at the A,B,C & D corners of the two-dimensional cube. An electron that is free to move is placed at the exact centre of the cube. Find out the direction in which electron will move?

• A. It will move toward $A$
• B. It will move toward $B$
• C. It will move toward $C$
• D. It will move toward $D$
• E. It will remain stationary

Answer 1

Answer: (D)

It will move toward $D$

The electron is placed at equal distances from the four given charges at four corners of two-dimensional cube (square).

Given four charges have the amount of charge

$\alpha =2e$

$\beta =-e$

$proton=e$

two $\alpha$ particles exert force equal on electron at centre in opposite direction therefore will cancel each other, net force by $\alpha$ particles is zero ,now proton attracts the electron towards D and $\beta$ particle repels the electron in the same direction towards D it means proton and $\beta$ particle are exerting force on electron in the same direction so electron will move toward D.