Question

A car battery has an emf of 12 V. If the internal resistance of the battery is 0.5 ohm, then the maximum current that can be drawn from the battery will be

30 A
24 A
20 A
6 A

Answer 1

▶$\large\bf\underline {To \: find:-}$

• we need to find the maximum current drawn from battery

⚘$\huge\bf\underline{Solution:-}$

▶$\bf\underline{\red{Given:-}}$

● potential difference = 12V

● Resistance = 0.5 Ω

● Current = ?

we know that,

★ According to Ohm's law potential difference is directly proportional to current and resistance is constant .

So,

• ⚘ By using ohm's law
• V = IR

Where,

• V = potential difference
• I = current
• R = Resistance

⇝ 12 = I × 0.5

⇝ I = 12/0.5

⇝ I = 120/5

⇝ I = 24 Ampere

Hence,

the maximum current that can be drawn from the battery will be 24A

So,

• Option 2nd 24A is correct answer.

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Answer 2

ANSWER :-

Given,

The E. M. F of battery (E) is 12 volt.

The internal resistance (r) is 0.5 ohm

When no external resistance in battery -

$i.e \: R (ext.) = 0$

Now,

According to Kirchoffs law - >

$E - (r × I )- R(ext.) × I = 0 \\ \\ 12 \: volt \: - (0.5 \times I) - 0 \times I = 0 \\ \\ 12 \: volt \: - \: 0.5 \: I \: - 0 \: = 0 \\ \\ 0.5 \: I \: = 12 \: volt \: \\ \\ = > I = \frac{12}{0.5 } \\ \\ = > I = \frac{120}{5} \\ \\ = > I = 24 \: ampere$

Hence, the maximum current that can be drawn from the battery will be 24 Ampere.

Option ( b ) is the correct one.