01 Conductors, P.D & Current - Warm-Up

Insulators cannot conduct electric current because they have no charge carriers.

• True

• False

Answer explanation

It is not true that insulators have no charge carriers. They have many billions of charge carriers, but they are unable to move through the material without a large amount of energy being applied.

Conductors have mobile charge carriers that can flow through the material under the influence of an applied electric potential difference.

Electric potential difference is the ​ (a)   done per unit ​ (b)   in moving a ​ (c)   charge between two points along the path of the current.

• work
• charge
• positive
• force
• mass
• negative

Answer explanation

This is the definition of electric potential difference.

The current through a light bulb is 0.4 A. Calculate the time it takes for 85 C of charge to pass through the light bulb. Give your answer to an appropriate number of significant figures and unit.

A 3 V cell transfers 15 J of energy in 2.0 s. Calculate the current leaving the cell.

• 5.0A

• 2.5 A

• 2.0 A

• 1.0 A

• 4

• 2

• 1