(Example 1 )
If the Voltage that furnishes the current is an ideal (no internal resistance) Voltage source. Then;
V/R = i
V/2R = i/2 If external resistance doubles, current reduced to 1/2 of original value
V/3R = i/3 If external resistance triples, current reduced to 1/3 of original value
(Example 2)
But if the Voltage that furnishes the current is a practical [contains an internal resistance (Ri)] Voltage source. Then the current is a function of the Voltage source`s internal resistance, which does not double nor triple, plus the external resistance which is being doubled and tripled.
V/(R + Ri) = i
V/(2R + Ri) = greater than i/2 but less than I.
V/(3R + Ri) = greater than i/3 but less than i/2