Grade 12Electric Current

The current in a circuit with an external resistance of 3.75 ohm is 0.5 . when a resistance of 1ohm is introduce into the circuit the current becomes 0.4 .Then what will be the emf of the power source ?

jogesh

8 Years agoGrade 12

2 Answers

Eshan

Approved Tutor Answer8 Years ago

Let the EMF and internal resistance of the battery be $E$ and $r$ , respectively.

When external resistance of $3.75\Omega$ is connected,

$E=i(R+r)$
$\implies E=0.5(3.75+r)$
When external resistance of $1\Omega$ is added to the circuit,

$E=i(R+R_1+r)$
$\implies E=0.4(3.75+1+r)=0.4(4.75+r)$
$E=2V$

Gitanjali Rout

Approved Tutor Answer8 Years ago

q] The current in a circuit with an external resistance of 3.75 ohm is 0.5 . when a resistance of 1ohm is introduce into the circuit the current becomes 0.4 .Then what will be the emf of the power source ?

$E=2V$ $\implies E=0.4(3.75+1+r)=0.4(4.75+r)$ $E=i(R+R_1+r)$ is added to the circuit, $1\Omega$ When external resistance of $\implies E=0.5(3.75+r)$ $E=i(R+r)$ is connected, $3.75\Omega$ , respectively.When external resistance of $r$ and $E$ Let the EMF and internal resistance of the battery be