How does energy flow from voltage source to resistor in a simple DC circuit?

Let us consider a simple dc circuit consisting of a battery and a resistor connected by ideal wires. As we know, current starts to flow thorugh the resistor and heat is generated as a result of this current flow. We need to determine how this energy is transferred from the voltage source to the resistor. The answer, suprisingly, is that the ideal wires connecting the battery to the resistor carry no energy at all. Most of the energy flows around the ideal wires. This is because the electric field inside the wires is zero and according to the Poynting theorem, no energy can flow if the electric field is zero in any given region of space. However, a radial electric field exists outside the current carrying wires and hence energy flows parallel to the wires and gets converted to heat in the resistor. 

SH
Answered by Sree Harsha N. Physics tutor

2892 Views

See similar Physics A Level tutors

Related Physics A Level answers

All answers ▸

Calculate the length of a 120m (as measured by the astronaut) spaceship travelling at 0.85c as measured by a stationary observer


How, given the threshold frequency and the kinectic enery of a photon, do you determine the frequency of the phton?


A small ball of mass 150 g is placed at a height of 20cm above the ground on an incline of 35°. It is released and allowed to roll down the slope; what will be the ball's speed when it reaches the ground? Assume friction and air resistance can be ignored.


A rock has a mass of 100g and it is thrown across a pond at a speed of 30ms^-1. Calculate the de Broglie wavelength of the rock and explain whether you can see the wave produced.


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

MyTutor is part of the IXL family of brands:

© 2025 by IXL Learning