A student connects up the circuit shown. How much current passes through the ammeter? A 9 V battery connected to R1 = 1 Ω in series, followed by two resistors in parallel, R2 = 4 Ω and R3 = 4 Ω, with an ammeter A in the bottom wire.

A student connects up the circuit shown.

MediumOriginal question

A student connects up the circuit shown. How much current passes through the ammeter?

1 ACorrect answerYour answer1.5 ACorrect answerYour answer3 ACorrect answerYour answer9 ACorrect answerYour answer

Show the answer and explanation

CorrectNot quiteAnswer C

Correct answer: C

R2 and R3 (4 Ω each) in parallel make 2 Ω; with R1 in series the total is 1 + 2 = 3 Ω.
The ammeter is in the main line: I = 9 ÷ 3 = 3 A.

Worth noting

1 A adds all three resistors in series (9 Ω); 1.5 A is the current in one of the parallel branches.

Ten questions from Everyday Physics, at your own pace.

Ten questions from Everyday Physics, at your own pace.