A charge particle q is projected in an electric field produced by a fixed point charge Q as shown in figure. Mark the correct statements.

Options

A. The path taken by q is a straight line.
B. The path taken by q is not a straight line.
C. The minimum distance between the two particles is `((qQ)/(2piepsilon_0) + sqrt((qQ)/(2piepsilon_0) + 4m^2u^2a^2))/(2m u^2)`
D. Velocity of the particle q is changing in both magnitude and direction.

Answer

B, C, D

Explanation

b.,c.,d.
The path traced by `q` is shown in Fig. `SAI.58`, The path is curvilinear and acceleration is due to the force exerted by `Q` on `q`. The separation between them is minimum if relative velocity of the particle along the line joining them is zero. Let `d` be the minimum separation between them. As torque about `Q` is zero, angular momentum remains conserved.
`mua=mvd` or `v=(ua)/(d)`
From energy conservation law, `(mu^(2))/(2)=(mv^(2))/(2)+(1)/(4piepsilon_(0))(qQ)/(d)`