Meters
State how to connect an ammeter and voltmeter to measure a resistor and explain ideal resistances.
STRUCTURED PRACTICE
D.C. circuits
Attempt each visible question before revealing support.
Junction
2.4 A enters a node. Branch currents 0.65 A and 0.80 A leave. Find the third outgoing current.
Loop
A 10 V source drives 2 Ω and 3 Ω in series. Find I and each drop.
Mixed network
Find total R for 12 Ω parallel 6 Ω, in series with 5 Ω.
Internal resistance
ε = 9.0 V, r = 0.40 Ω, R = 4.1 Ω. Find I, V and lost volts.
Loaded divider
4 kΩ above and 6 kΩ below are across 10 V. A 6 kΩ load is placed across the lower resistor. Find Vout.
LDR divider
An LDR is above a fixed lower resistor. Predict Vout across the fixed resistor as light increases.
Null method
Cells balance at 60 cm and 45 cm. If the second is 1.35 V, find the first and explain accuracy.