# A battery has an emf of \varepsilon = 3V, an internal resistance r = 12 \Omega, and is connected...

## Question:

A battery has an emf of {eq}\varepsilon = 3V {/eq}, an internal resistance {eq}r = 12 \Omega {/eq}, and is connected to a resistor of {eq}R =55 \Omega {/eq}.

a . Express the current {eq}I {/eq} through {eq}\varepsilon, r {/eq} and {eq}R {/eq}

b . Calculate the numerical value of {eq}I {/eq} in {eq}A {/eq} .

c . Express the terminal voltage {eq}\Delta {/eq} through {eq}I {/eq} and {eq}R {/eq} .

d . Calculate numerical value of {eq}\Delta {/eq} in {eq}V {/eq} .

## Ohm's Law:

When we have a simple series circuit with a supply *E* and a series equivalent resistance *R*, we determine the current in the circuit as the ratio of the emf to the resistance i.e. {eq}E = \frac{E}{R} {/eq}. This relationship is called Ohm's Law. The equivalent series resistance is the resistance value that can replace all the resistors without changing the current supplied in the circuit.

## Answer and Explanation:

#### Part a

By Ohm's Law, the current *I* is the ratio of voltage to the equivalent resistance of the series circuit, i.e.

{eq}I = \frac{V}{R} =...

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#### Learn more about this topic:

from Physics 112: Physics II

Chapter 9 / Lesson 5