Question

A battery after a long use has an emf
24 V and an internal resistance 380
Calculate the maximum current drawn
from the battery? Can this battery drive
starting motor of car?

ans showld be 0.068 A


i want the solution ​

Answer 1

it is given that, emf (electromotive force) of the battery, E = 24 V

internal resistance of the battery, r = 380 Ω

Let maximum current drawn from the battery is I

according to Ohm's law,

E = Ir

or, 24 V = I × 380 Ω

or, I = 24/380 ≈ 0.06315 A

you know as well, The starter motor requires a large current (~ 100A) for a few second. but here only 0.06315A current is available .so, it is not possible to drive the starter motor of a car with the given cell.

Answer 2

The maximum current drawn from the battery is 0.063 Ampere

Explanation:

Given as :

The emf of the battery after long use = 24 volts

The internal resistance of battery = r = 380 ohm

Let The maximum current drawn from the battery = i Ampere

According to question

From the Ohm's law

Emf induced in the battery = current × internal resistance

So, emf = i × r

The maximum current = i = $\dfrac{Emf}{r}$

Or,                                    i = $\dfrac{24 volt}{380 ohm}$

i.e                                     i = 0.063 ampere

So, The maximum current drawn from the battery = i = 0.063 Ampere

Now,

As starter motor requires a large current  for a few second. but here we get only current of 0.063. Ampere . so, it is not complicated to drive the starter motor of a car with 0.063 A current .

Hence, The maximum current drawn from the battery is 0.063 Ampere Answer