Question

A secondary cell after long use has an emf of $1.9V$ and a large internal resistance of $380\Omega$. What maximum current can be drawn from the cell? Could the cell drive the starting motor of a car?

• A. $5mA$, yes
• B. $<5mA$, Yes
• C. $5mA$, No
• D. $<5mA$, No

Answer 1

The correct option is A $5mA$, yes

Emf of cell, $E=1.9V$

Internal resistance,$r=380\Omega$

$I_{max}=\frac{E}{r}$

$=\frac{1.9}{380}=0.005A$

The amount of current drawn from the cell is enormously and thus cannot drive a starting motor of a car.