Electric Power Practice Test

A device is connected to a constant $6.0\ \text{V}$ source for several seconds. During this interval, its current decreases from $2.0\ \text{A}$ to $1.0\ \text{A}$. Compared to the start, the device’s electric power is

A resistor is connected across a constant-voltage source for $4\ \text{s}$. The source voltage is increased from $V$ to $2V$ while the resistor’s resistance stays constant. Compared to before, the resistor’s power dissipation is