The bench again. The 12 V battery stays put, and only the resistor is swapped. With 40 Ω in the loop, the ammeter reads 0.30 A. With 120 Ω, it reads 0.10 A.
The voltage never changed, so the fall in current has one cause. The 120 Ω resistor opposes the current more strongly, so less charge gets around the loop each second.
This pattern is sharp too. Triple the resistance, and the current falls to a third. Halve the resistance, and the current doubles.
A 10 Ω resistor across a battery is replaced with a 30 Ω resistor. The battery is unchanged. What happens to the current?
Write down the fact:
The resistance increased, and the voltage did not change.
Increasing the resistance decreases the current.
The current gets smaller.
A circuit's resistance is halved. The voltage is unchanged. What happens to the current?
Write down the fact:
Halving the resistance halves the opposition to the current.
So the current doubles.
The current doubles.
A 20 Ω resistor is swapped for a 60 Ω resistor. The battery is unchanged. What happens to the current?
A dimmer knob lowers a circuit's resistance. The voltage is unchanged. What happens to the current?
A circuit's resistance is tripled. The voltage is unchanged. What happens to the current?
In an intercom circuit, a 50 Ω coil is replaced with a 200 Ω coil. The supply is unchanged. What happens to the current?
Which change increases the current in a circuit, with the voltage unchanged?
A heater's element is swapped for one with double the resistance. The voltage is unchanged. What happens to the current?