Question

A battery has an emf of 8.66 V and produces a current of 12.37 A when connected across its terminals. What is its internal resistance

Answer 1

0.7 ohms

Explanation

battery has its own opposition to the flow of the current

This is Internal Resistance,to solve this we use the Ohm’s Law formula and Kirchhoff’s Voltage Law formula to calculate the Internal Resistance.

$\begin{gathered} V=IR \\ where\text{ V is the voltage } \\ R\text{ is the resitance} \\ I\text{ is the current} \end{gathered}$

so

Step 1

a) let

$\begin{gathered} V=8.66\text{ v} \\ I=12.37\text{ A} \\ R=R(\text{ unknown\rparen} \end{gathered}$

b) now, replace in the formula and solve for R

$\begin{gathered} V=IR \\ divide\text{ both sidesby I} \\ \frac{V}{R}=\frac{IR}{I} \\ R=\frac{V}{I} \\ R=\frac{8.66\text{ v}}{12.37A} \\ R=0.7\text{ }\Omega \end{gathered}$

so,the answer is

0.7 ohms

I hope this helps you