A battery of emf 10 V internal resistance `3 Omega` is connected to a resistor R.
(i) If the current in the circuit is 0.5 A. calculate the value of R.
(ii) What is the terminal voltage of the battery when the cirucit is closed.

Explanation

Here `E = 10 V, r = 3 Omega, I = 0.5 A, R = ?, V = ?`
`I = (E )/(R + r) "or" (R + r) = (E )/(1) = (10)/(0.5) = 20` or
`R = 20 - r = 20 - 3 = 17 Omega`
Terminal voltage `V = IR = 0.5 xx 17 = 8.5 Omega`