Final answer:
The brightness of a light bulb is determined by its power dissipation, which is affected by the bulb's resistance. Lower resistance allows more current to flow at a given voltage, producing more light.
Step-by-step explanation:
The brightness of a light bulb is closely related to the electrical power it dissipates, which can be defined as the rate at which it converts electrical energy into light and heat. Using Ohm's law, we can understand this relationship in terms of voltage (V), current (I), and resistance (R). For a fixed voltage, a light bulb with a lower resistance will draw more current, leading to a higher power dissipation (P = I²R) and thus brighter illumination. Conversely, if resistance increases while keeping the voltage constant, the current decreases, resulting in less electrical power and dimmer light (P = V²/R).