Question

# A battery of emf $$E$$ and internal resistance $$r$$ is connected across a resistance $$R$$. Resistance $$R$$ can be adjusted to any value greater than or equal to zero. A graph is plotted between the current $$(i)$$ passing through the resistance and potential difference $$(V)$$ across it. Select the correct alternative(s).

A
internal resistance of battery is 5 Ω
B
emf of the battery is 20V
C
maximum current which can be taken from the battery is 4A
D
Vi graph can never be straight line as shown in the figure

Solution

## The correct option is A internal resistance of battery is $$5\space\Omega$$Some devices having negative resistance show the inverse variation between voltage and current as shown in given figure(in problem).The terminal voltage of the battery is given by$$V = E - Ir$$.............................................................(1)where, $$r$$ is the internal resistance of battery.when $$I = 0, V = E$$. Hence, $$E = 10$$V.Now, from graph, if  $$V = 5$$V, $$I = 1$$A, therefore$$5 = 10 - (1)r$$...................................................from(1)$$r = 5 \Omega$$The maximum current which can be taken from the battery is$$I = \dfrac{E}{r} = \dfrac{10}{5} = 2A$$Physics

Suggest Corrections

0

Similar questions
View More

People also searched for
View More