2
$\begingroup$

There is a question in my textbook:

A current of $7\ \mathrm{A}$ goes through the heating element in a hair-drier. The voltage of the heating element is $240\ \mathrm{V}$.

b) How many joules of energy does each coulomb supply to the element as it goes through?

I understand this is a simple problem.

So it's 240 volts. Can this just be changed to 240 joules per coulomb? Is voltage and energy per unit charge related?

$\endgroup$
  • $\begingroup$ I fixed up some confusion between units and the quantities they measure in the edit I made. $\endgroup$ – David Z May 13 '17 at 3:46
  • $\begingroup$ Joules express energy, Coulombs charge, and Amps current (charge/second). Can you take it from here? $\endgroup$ – hdhondt May 13 '17 at 4:04
  • $\begingroup$ Two points differ in potential by one volt if the work done in taking one coulomb between those two points is one joule. $\endgroup$ – Farcher May 13 '17 at 5:29
  • $\begingroup$ You're absolutely correct $\endgroup$ – Ofek Gillon May 13 '17 at 8:16
1
$\begingroup$

$1$ J is the work done in taking 1 C between a potential difference of 1 V. Then, since the electric work is $qU$, $1\, J = 1\, C\cdot V$, or $1\,V = 1\,J/C$: you were right.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.