Question

A uniform electric field contains a number of particles. All are experiencing forces in the same direction as the electric field. What can be concluded from this?
All the particles have negative charges.
All the particles have positive charges.
All the particles are charged, but they may be positive or negative.
All the particles must be uncharged.

Answer 1

Answer: D

All the particles must be uncharged

Explanation:

If all the particles are positively charged, then there will be force of repulsion between them which will give different directions away from each other. The same is applicable if they are all negatively charged.

If the particles are positively and negatively charged, their will be force of attraction between them which will give different directions towards each other.

For all to be experiencing forces in the same direction, We can conclude that

All the particles must be uncharged.