Two resistors, with resistances 5Ω and 10Ω respectively are to be connected to a battery of emf 6V so as to obtain:
Minimum current flowing
Maximum current flowing
i) How will you connect the resistances in each case?
ii) Calculate the strength of the total current in the circuit in the two cases.
Given: R1 = 5Ω
R2 = 10Ω
EMF = 6V
i) To obtain minimum current, we should connect the two resistors in series. To obtain maximum current, we should connect the two resistors in parallel.
ii) Calculation of strength of the total current in both the cases:
I case: Resistors in series
When several resistors are joined in series, then the total resistance (Rs) is equal to:
Rs = R1 + R2
• Rs = 5Ω + 10Ω = 15Ω
To calculate the flowing current (I), apply the Ohm’s law:
V = IR
• 
• I = 0.4A
Thus, by connecting the resistors in series, the minimum current flowing is 0.4A.
II case: Resistors in parallel
When several resistors are joined in series, then the total resistance (RP) is equal to:
• 
• 
• 
To calculate the flowing current (I), apply the Ohm’s law:
V = IR
• 
• I = 1.8A
Thus, by connecting the resistors in parallel, the maximum current flowing is 1.8A.