Which of the following materials is an insulator against electric current?
a. a silver spoon
b. aluminum foil
c. a copper penny
d. a glass pane

The correct answer is "a glass pane".

Explanation:

Insulator is the material in which the electrons does not flow. The flow of electrons constitutes the electric current. It has high resistance. Therefore, it does not conduct electric current.

For example, plastic, rubber, glass pane etc.

Conductor is the material which allows the flow of electrons. Therefore, it conducts the electric current. It has low resistance. For example, metal.

Aluminium foil, silver spoon and copper penny conduct the electric current.

Therefore, the correct option is "a glass pane".

i think the answer is a, hope this : )

answer: 2×10^-2kg

explanation: density= mass per volume

vol=mass/density

converting to s.i units we have;

3÷1000kg = 0.003

1.5÷100m = 0.15

0.003/0.15 = 0.02kg