P4.6 Parallel Circuits

Question 1

In a parallel circuit, how is total current related to branch currents?

Answer 1

Total current = sum of the currents in each branch.

Question 2

What is the potential difference across components in parallel?

Answer 2

The p.d. across each component in parallel is the same.

Question 3

Why is p.d. the same across all parallel components?

Answer 3

Each branch is connected across the cell, so the potential difference (voltage) across each branch is the same.

Question 4

How does resistance of a branch affect current in that branch?

Answer 4

Higher resistance → smaller current.
Lower resistance → larger current.

Question 5

What happens to total resistance when you add more resistors in parallel?

Answer 5

Total resistance decreases.

Question 6

What is the total resistance of two (or more) components in parallel?

Answer 6

It is less than the resistance of the component with the least resistance.

Question 7

Why does adding a resistor in parallel decrease total resistance?

Answer 7

It creates an additional path for the current.

Question 8

If components are in parallel, what determines the current through each component?

Answer 8

Their individual resistance, since p.d. is the same across each.