Charging materials by friction
4 marks · NormalA student wants to separate conductors from insulators using a test circuit with a lamp.
State two materials that would make the lamp light in this circuit.
State two materials that would NOT make the lamp light in this circuit.
Explain why the materials stated in part (a) are conductors of electricity, while those in part (b) are not.
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) e.g. copper, graphite, aluminium
(b) e.g. plastic, glass, rubber, wood
(c) Conductors have free electrons that allow electric current to flow; insulators do not allow electrons to move freely.
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · Any correct conductor stated, e.g. copper/graphite/aluminium.
B1 (b) · 1 mark · Any correct insulator stated, e.g. plastic/glass/rubber/wood.
M1 (c) · 1 mark · States that conductors have free electrons or allow charge to flow.
M1 (c) · 1 mark · States that insulators do not allow charge to flow or lack free electrons.
Worked solution
a) Any two from: copper, graphite, aluminium (other metals are acceptable).
b) Any two from: plastic, glass, rubber, wood.
c) Conductors, like metals, have free electrons that enable the electric current to flow through them. Insulators, such as plastic and glass, do not have these free electrons, so electricity cannot pass through them easily.