Question

A particle of mass m and charge $q$ is thrown in a region where uniform gravitational field and electric field are present. The path of particle :

• A. may be straight line
• B. may be a circle
• C. may be a parabola
• D. may be a hyperbola

Answer 1

Answer: (A), (C)

The correct options are
A may be straight line
C may be a parabola

The acceleration due to gravity is insignificant compared with the acceleration caused by the electric field, so gravitational field can be ignored. Hence, when a particle of mass m and charge q is thrown in a region where uniform gravitational field and electric field are present, before entering electric field, the charge follows a straight line path (since, no net force due to any of the field). As soon as it enters the field, the charge begins to follow a parabolic path (since, constant force always in the same direction). As soon as it leaves the field, the charge follows a straight line path (since, no net force due to any of the field). The path of particle may be straight line or may be parabola.