Question 642: Current Electricity

Question

The internal resistance of a 2.1 V cell which gives a current of 0.2 A through a resistance of 10 $\Omega $ is

Accepted Answer

$I = {\varepsilon  \over {R + r}}$
$ \Rightarrow IR + Ir = \varepsilon $
Here,
$R = 10\Omega ,r = ?,\varepsilon  = 2.1V,I = 0.2A$
$ 	herefore $ 0.2 ÃÂ 10 + 0.2 ÃÂ r = 2.1
2 + 0.2r = 2.1
0.2r = 0.1 $ \Rightarrow $ r = ${1 \over 2}$ = 0.5 $\Omega $

Answer

0.8 $\Omega $

Answer

1.0 $\Omega $

Answer

0.2 $\Omega $

Answer

0.5 $\Omega $

Current Electricity

The internal resistance of a 2.1 V cell which gives a current of 0.2 A through a resistance of 10 \Omega is

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