The MCAT has been known to ask questions involving the distinction between the total EMF produced by a galvanic cell and the voltage supplied to the external circuit elements. Remember that the power cell or battery in a DC circuit supplies the electromotive force (emf), or voltage, to the entire circuit, not just the external circuit elements, but also including the power source's internal resistance. This means that the external voltage of the battery will be less than the emf because it also takes work to move charges over the internal resistance. Because V = e - IR, when the current is zero, the external voltage equals the EMF.

The WikiPremed MCAT Course is a comprehensive course in the undergraduate level general sciences. Undergraduate level physics, chemistry, organic chemistry and biology are presented by this course as a unified whole within a spiraling curriculum. Please read our policies on Privacy and Shipping & Returns.  Contact Us. MCAT is a registered trademark of the Association of American Medical Colleges, which does not endorse the WikiPremed Course. WikiPremed offers the customers of our publications or our teaching services no guarantees regarding eventual performance on the MCAT.

Creative Commons License
WikiPremed is a trademark of Wisebridge Learning Systems LLC. The work of WikiPremed is published under a Creative Commons Attribution NonCommercial ShareAlike License. There are elements of work here, such as a subset of the images in the archive from WikiPedia, that originated as GNU General Public License works, so take care to follow the unique stipulations of that license in printed reproductions.