Question

A dc source of emf E1=100V and internal resistance r=0.5 ohms. A storage battery of emf E2=90V and an external resistance R are connected as shown in figure .for what value of R no current will pass through the battery​

Answer 1

Answer:

from diagram we can say...90/r=100/r.5

so r=4.5

Answer 2

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$\: \large \green{ \bold{ \underline{ \underline{ answer \to}}}}$

$\: \underline{ \bf{ \color{pink} \: given}}$

$\bullet\tt{emf \: e1 = 100 \: v}$

$\bullet \tt \: r = 0.5ohms$

$\: \to \underline{ \bf{to \: find \: the \: value \: of \: r}}$

$\: \sf : \implies for \: no \: current \: the \: flow \: through \: battery$

$\\ \implies\sf{\dfrac{E}{V}=\dfrac{R+r}{R}}$

$\\ \implies\sf{\dfrac{100}{90}=\dfrac{R+0.5}{R}}$

$\\ \implies\sf{\dfrac{10}{9}=\dfrac{R+0.5}{R}}$

$\\ \implies\sf{10R=9R+9\times 0.5}$

$\\ \implies\sf{10R=9R+4.5}$

$\\ \implies\sf{R=4.5}$

$\bullet \underline{\boxed{\tt{the \: value \: of \: R \: is \: 4.5}}}$