Question

An ideal battery is put in a simple (series) circuit with an incandescent bulb ('A') which lights. The bulb is then replaced with a second bulb ('B'), which also lights but is dimmer than ' A ' was. Which of the following decreased between the use of Bulb ' A ' and Bulb ' B '?

Answer 1

The decreased brightness of bulb 'B' compared to bulb 'A' when connected to an ideal battery in a simple circuit likely indicates a decrease in current due to an increase in resistance.

Step-by-step explanation:

When an ideal battery is put in a simple circuit with an incandescent bulb 'A' that lights up and then replaced with bulb 'B' which lights up dimmer, one physical quantity that likely decreased is the current through the bulb. This decrease in brightness can be due to an increase in the resistance of bulb 'B' compared to bulb 'A'. According to Ohm's law, for the same voltage provided by the ideal battery, an increase in resistance would result in a lower current, and since the power (and therefore brightness) of a bulb is related to both the current and voltage (P=IV where P is power, I is current, and V is voltage), a reduction in current would lead to a dimmer bulb. A higher resistance in bulb 'B' would also imply that it converts less electrical energy to light and more to heat compared to bulb 'A'.