Problems with static electricity
3 marks · EasyThe diagram shows smoke particles in a chimney. The smoke is passed through a mesh of highly charged wires and then through plates connected to earth.
Explain why the dust particles gain a charge as they pass through the mesh.
Explain why the charged dust particles are attracted to the earthed plate.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
(a) The mesh is highly charged, so dust particles become charged as they pass through (usually by gaining electrons).
(b) Charged particles are attracted to the earthed (neutral or oppositely charged) plate, so they move towards and stick to it.
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · Mentions that particles gain charge from the charged mesh (e.g., by gaining electrons).
B2 (b) · 1 mark · States the plate is earthed (neutral/oppositely charged).
B3 (b) · 1 mark · States charged particles are attracted and stick to plate (or says opposite charges attract).
Worked solution
a) The mesh is highly charged, so as dust passes through, it picks up extra charge, typically becoming negatively charged.
b) The dust is now charged. The earthed plate is able to attract these oppositely charged particles, so they stick to it and are removed from the smoke.