What is the net resistance of two resistors 10 ohm and 40 ohm connected in parallel?

Correct option is A

The correct answer is (a) 8 ohm.

Explanation: When two resistors are connected in parallel, the total or net resistance ( net R net ) is given by the formula: $$\frac{1}{R'}$$​ = $$\frac{1}{R1}$$​ + $$\frac{1}{R2}$$​​

Where: R1 and R2 are the individual resistances of the two resistors, R' is the net resistance of the combination.

R1= 10 Ohm

R2= 40 ohm

​$$\frac{1}{R'}$$​​= $$\frac{1}{10}$$​​+ $$\frac{1}{40}$$ = $$\frac{5}{40}$$​​

Thus, R'= 8 ohm.

Information Booster:

• When resistors are connected in parallel, the total resistance is always less than the smallest individual resistance in the group. This is because the parallel connection provides multiple paths for the current, effectively lowering the overall resistance.
• The formula for parallel resistance is derived from the fact that in a parallel circuit, the total current is the sum of the currents through each resistor, and resistance is inversely related to current.