A cell of e.m.f. 1.5 V, internal resistance 1 `Omega ` is connected to the resistors of 4 `Omega ` and `20 Omega ` in series. Draw a circuit diagram and calculate :
the current in the circuit,

Explanation

The circuit diagram of the arrangement is shown in Fig.

total resistance of the circuit
`R = R_1 +R_2 +r = 4 + 20 +1 = 25 Omega `
Current in the circuit
` I= ( e.m.f)/( " total resistance ") = ( 1.5 )/(25) = 0.06 A `