Chapter 21: CIRCUITS, BIOELECTRICITY, AND DC INSTRUMENTS (Exam 2)

What is a series circuit?

Components share the same current.

What is the equivalent resistance in series?

Rs = R1 + R2 + R3 + …

What is a parallel circuit?

Components share the same voltage.

What is the equivalent resistance for two parallel resistors?

Rp = (R1R2)/(R1 + R2).

What happens to voltage across parallel resistors?

It is the same across each resistor.

What happens to current in a parallel circuit?

Current splits between branches.

What is emf?

The maximum potential difference of a source; measured in volts.

What is internal resistance?

Resistance inside a battery or generator.

What is terminal voltage?

The actual voltage between a battery's terminals.

What does an ammeter measure?

Current.

How is an ammeter connected?

In series.

What resistance should an ideal ammeter have?

Zero resistance.

What does a voltmeter measure?

Voltage between two points.

How is a voltmeter connected?

In parallel.

What resistance should an ideal voltmeter have?

Infinite resistance.

What is Kirchhoff's junction rule?

Current in = current out.

What does the junction rule conserve?

Electric charge.

What is Kirchhoff's loop rule?

Total voltage rises = total voltage drops.

What does the loop rule conserve?

Energy.

What is an RC circuit?

A circuit containing a resistor and capacitor.

What happens when an RC capacitor charges?

Current decreases as the capacitor charges.

What is the RC time constant?

τ = RC.

What happens after one time constant during charging?

Capacitor reaches 63.2% of final voltage.

What happens after one time constant during discharging?

Voltage falls to 36.8% of its initial value.

What is the capacitor charging equation?

V = emf(1 − e⁻ᵗ/ᴿᶜ).

What is the capacitor discharging equation?

V = V₀e⁻ᵗ/ᴿᶜ.

What happens when a capacitor is fully charged?

Current stops and Q = C·emf.