Question

A 12 V battery is connected across a device with variable resistance. As the resistance of the device increases, determine whether the following quantities increase, decrease, or remain unchanged.

a) Current
b) Voltage
c) Power
d) Resistance

Answer 1

When resistance in a device connected to a 12 V battery increases, current decreases, power decreases, voltage remains the same, and resistance increases. In a parallel circuit with two resistors, if one resistor's resistance increases, the current through and voltage across the other resistor remain unchanged.

Step-by-step explanation:

When a 12 V battery is connected across a device with variable resistance, the following will occur:

• Current (I): As resistance (R) increases, current will decrease according to Ohm's law (I = V/R), where V is voltage.
• Voltage (V): The voltage across the device will remain unchanged because it is determined by the battery's output of 12 V.
• Power (P): Power will decrease because power is calculated as P = I^2 * R. As current decreases, so does power.
• Resistance (R): By the scenario's definition, resistance is increasing.

For a situation with two identical resistors in parallel, if the resistance of one resistor is increased:

• The current through the unchanged resistor remains the same, and
• The voltage across the unchanged resistor remains the same.

These conclusions arise from the property of parallel circuits where each component receives the full voltage of the source.