Current Electricity - Voltage and Current

We are given charge $Q=45\text{ C}$ and time $t=9\text{ s}$. We need to find the current $I$.

Use the formula $I=\frac{Q}{t}$ Substituting: $I=\frac{45}{9}=5\text{ A}$

The current is 5 A. The unit ampere (A) is correct because we divided coulombs by seconds.

We need to find current using $I=\frac{Q}{t}=\frac{45}{9}$. The correct answer must equal 5 A.

0.2 A would result from dividing $t$ by $Q$: $\frac{9}{45}=0.2$. This is the formula inverted — incorrect.

405 A would result from multiplying $Q\times t=45\times 9=405$. Multiplying is not the correct operation here.

36 A would result from subtracting $45-9=36$. Subtraction has no relevance to this formula.

The only remaining option is 5 A, confirmed by $I=\frac{45}{9}=5\text{ A}$.

Conventional current flows from positive to negative through the external circuit. This is a historical convention established before electrons were discovered.

Electrons carry negative charge and actually move in the opposite direction to conventional current. So if conventional current goes positive → lamp → negative, electrons travel negative → lamp → positive.

The correct description is that electrons flow from the negative terminal, through the lamp, to the positive terminal — the opposite direction to conventional current.

The question asks what actually happens at the atomic level, which means we need the direction of electron flow, not conventional current.

'Electrons flow from the positive terminal to the negative terminal' is incorrect — this describes conventional current direction, not electron flow.

Protons are fixed inside atomic nuclei and do not move through wires. This option is physically impossible in a metallic conductor.

Electrons and conventional current flow in opposite directions — this is a fundamental point. Conventional current is positive to negative; electron flow is negative to positive.

'Electrons flow from the negative terminal, through the lamp, to the positive terminal' is correct — electron flow is always opposite to conventional current direction.