Question

A battery of e.m.f 15 V and internal resistance 3 ohm is connected to two resistors of resistances 3 ohm and 6 ohm in series. The current through the battery is

• A. 1.25 A
• B. 3 A
• C. 1.5 A
• D. 5 A

Answer 1

The correct option is A 1.25 A

The total resistance of a circuit connected to the given cell of emf 15 V is the sum of all the resistances from various sources like, resistors, ammeter, voltmeter, etc., connected in series along with the internal resistance of the cell.

In this case, the total resistance is given as $3\Omega +3\Omega +6\Omega =12ohms$.

From the ohm's law the total current can be calculated from the formula $I=V/R$.

That is, $I=\frac{V}{R}=\frac{15V}{12A}=1.25A$.

Hence, the current through the battery is 1.25 amperes.