Two resistors, with resistances 5 Ω and 10 Ω respectively are to be connected to a battery of emf 6 V so as to obtain :
(i) minimum current flowing
(ii) maximum current flowing
(a) How will you connect the resistances in each case?
(b) Calculate the strength of the total current in the circuit in the two cases.
Given:
Two resistors with resistances R1 = 5 ohm and R2 = 10 ohm, V = 6 volt
(a) For minimum current these two should be connected in series. For maximum current these two should be connected in parallel.
(b) In series,
Total resistance = 5 + 10 = 15 ohms
Therefore total current drawn = V/R
= 6/15 = 0.4 amps
In parallel,
Total resistance R is given as
1/R = 1/R1 + 1/R2
1/R = 1/5 + 1/10
1/R = 3/10
R = 10/3 ohm
Therefore total current drawn by the circuit = V/R
= 6/(10/3) = 1.8 amps.