Electric current (A): charge, current and voltage
Answers are for parents and teachers.
1
A charge of 36 C passes in 9 s. Calculate the current.
I = 36 C ÷ 9 s = 4 A.
2
How much charge passes if 2 A flows for 2 minutes? (Convert to seconds first.)
2 min = 120 s. Q = 2 A × 120 s = 240 C.
3
60 J move 12 C. Find V. Then find the work to move 20 C at the same voltage.
V = 60 ÷ 12 = 5 V. W = 5 V × 20 C = 100 J.
4
A friend says the current is used up in the bulb and is smaller after it. Answer.
No: in a single loop the same current flows everywhere; the energy is what the bulb receives.
5
Draw a circuit with a cell, a lamp, an ammeter in series and a voltmeter across the lamp.
The ammeter is in the loop; the voltmeter is joined to the two ends of the lamp.