Charge & Current Flashcards

All 6 cards in this deck

What is electric current?

A flow of electrical charge; its size is the rate of flow of electrical charge.

What must a circuit include for electrical charge to flow?

A source of potential difference, and the circuit must be closed.

What is the equation linking charge flow, current and time?

charge flow = current × time, or $Q = It$

What units are used for charge flow, current and time in $Q = It$?

Charge in coulombs (C), current in amperes/amps (A), time in seconds (s).

What are the steps to calculate charge flow when the current is given in milliamps?
e.g. a current of 50 mA for 20 s

1. Convert current to amps: $50\text{ mA} = 0.050$ A
2. Write the equation: $Q = It$
3. Substitute: $Q = 0.050 \times 20 = 1.0$ C

True or false? In a single closed loop the current is smaller after it has passed through a lamp.

False. The current has the same value at every point in a single closed loop.