Question

A cell of emf 1.5v is connected in series with a resistor r and an ammeter resistance 0.2ohm . the p.d between the terminals of the cell is 1.35v and the ammeter reading is 0.3.calculate the value of r and the internal resistance

Answer 1

Answer:

$I_{T} =\frac{Emf}{RT + rt}$

$r_{t} = \frac{emf}{I_{T} } - R_{T}$

$r_{t} = \frac{1,5}{0,3} - 0,2$

$r_{t} =$ 4,8 Ω

Explanation:

• $I_{T} -$ it is the Total current measured in Amperes ($I$).
• $Emf$ - it is the Electromotive force measured in Volts (V).
• $R_{T}$ - it is the Total resistance measured in Ohms (Ω)
• $r_{t}$ - it is the total internal resistance measure in Ohms (Ω).

• Firstly, you should make $r_{t}$ the subject of the formula,

•   Secondly, place the values on the signs (symbols).
• Thirdly, Calculate and you will get the final answer.

The  final Answer is:

$r_{t}$ = 4,8 Ω