§-Quick questions
TASPhysicsUnit 3: Gravity and Electromagnetism
Quick questions on Electric fields and field lines - TCE Physics (Tasmania)
4short Q&A pairs drawn directly from our worked dot-point answer. For full context and worked exam questions, read the parent dot-point page.
What is electric field strength?Show answer
The electric field strength at a point is defined as the force per unit charge that a small positive test charge would feel:
What is the field of a point charge?Show answer
Around an isolated point charge the field is radial. Its strength follows the inverse-square law:
What are the uniform field between parallel plates?Show answer
Two parallel plates with opposite charge and a potential difference across a separation produce a uniform field in the gap:
What are reading field lines?Show answer
Field lines obey simple rules: they start on positive charge and end on negative charge, they never cross, and their density shows the field strength, so closely packed lines mean a strong field. The line through a point gives the direction of the force on a positive charge placed there. For two charges, the pattern shows attraction (lines linking them) or repulsion (lines pushed apart). The field is zero at any point where contributions cancel; for two like charges this neutral point lies on the line between them, closer to the smaller charge.
Have a question we have not covered?
This dot-point answer is short enough that we have not extracted many short questions yet. Read the full dot-point answer or ask Mo, our study assistant, in the chat for follow ups.