Does power of current increase or decrease as it flows through batteries vs resistors – [Free] B82

Answer

Detailed Explanation

In a simple series circuit consisting of a battery and a resistor:

• Current (I): The same current flows through all elements because of Kirchhoff’s Current Law.
• Power (P): The power associated with each component depends on the voltage drop across it. The power delivered or consumed is calculated as:
  P = I × V

Power in the Battery

The battery is the source of electrical energy. It converts chemical energy into electrical energy, thereby providing power to the circuit:

P_battery = I × V_battery

This represents the rate at which the battery does work to move charges through the circuit.

Although a real battery has internal resistance (causing some energy loss), the main concept is that the battery increases the energy per unit charge.

Power in the Resistor

A resistor does not supply energy; it consumes electrical energy by converting it into heat:

• The voltage drop across the resistor is determined by Ohm’s Law:
  V_resistor = I × R
• The power dissipated as heat is:
  P_resistor = I × V_resistor = I² × R

Summary: Increase vs. Decrease of Power

As current flows through the circuit:

• In the battery: The energy per unit time (power) increases because the battery does work on the charges.
• In the resistor: The energy is decreased as electrical energy converts into thermal energy.

The current itself remains the same, but the available electrical energy (and therefore power) is highest just after the battery and lowest after passing through the resistor.

Conclusion

The battery increases the power carried by the current by supplying energy, while the resistor decreases the power by dissipating it as heat.