Illuminate Your Understanding: Brightness and Resistance in Lamps

How does resistance affect the brightness of lamps when connected in parallel and series?

When two lamps with different resistances are connected in parallel, which lamp is brighter - the one with greater resistance or the one with less resistance? What about when the lamps are connected in series?

Answer:

The lamp with less resistance is brighter when connected in parallel as it draws more current. However, when connected in series, the lamp with greater resistance is brighter because the same current flows through both lamps and the power dissipation is higher for the lamp with greater resistance.

When considering the brightness of two lamps with different resistances, the one that will be brighter is the one that dissipates more power. For lamps connected in parallel and in series, the key is to understand how resistance affects current flow and power dissipation.

In a parallel circuit, each lamp receives the full voltage of the power source. Thus, the lamp with less resistance will draw more current and consequently dissipate more power, making it brighter. Therefore, for part (a) of the question, the answer is the lamp with less resistance.

In a series circuit, the current flowing through each lamp is the same because there is only one path for the current to take. Since the power dissipated in a resistor is proportional to the square of the current multiplied by the resistance (P = I^2R), the lamp with the greater resistance will dissipate more power and be brighter. Hence, for part (b) of the question, the answer is the lamp with greater resistance.

The correct answer to the student's question is option (b): (a) Lamp with less resistance; (b) Lamp with greater resistance.