Question

In an external electric field, the field line of force represent:

• A. the direction of the force experienced by a positively charged particle placed in the field
• B. the direction of the force experienced by a negatively charged particle placed in the field
• C. the direction that a negatively charged particle in the field would move
• D. how far the force field extends from the particle
• E. the strength of the force field

Answer 1

Answer: (A), (E)

the direction of the force experienced by a positively charged particle placed in the field
the strength of the force field

The force experience by a particle $q$ in a force field $\overrightarrow{E}$ is given by $\overrightarrow{F}=q\overrightarrow{E}$.

Thus of a positively charged particle, $q$ is positive, and hence the direction of force on the particle and the field is the same.
Thus it can be said that the field line of force represent the direction of the force experienced by a positively charged particle placed in the field.