. A battsistance r se1 d to an external resistance of R ,R1 2 respectively. Find the

Question

 net



14. A battery of emf

E

and internal resistance

r

sends a current,

1 2 I ,I

when connected to an external resistance of

R ,R1 2

 respectively. Find the

emf. and internal resistance of the battery.

Answer 1

E

is the emf of a battery

r

is the internal resistance which sends currents

1 2 I ,I R ,R1 2

are external resistances

Current

1

I

can be written as:

1

1

E

I

R r





E I (R r)   1 1

 ……(1)

Similarly,

E I (R r)   2 2 ……(2)

From equations

(1)

and

(2) 1 1 2 2     I (R r) I (R r) 2 1 1 1 2 2     I r I r I R I R     r I I I R I R  2 1 1 1 2 2