A wire having a resistance of 90 ohm is cut into three equal parts. The three equal parts are then joined in parallel. What is the value of the resistance of the combination ?

Explanation

We are given: A wire having resistance `90 Omega`
We know that, when wire of `90 Omega` resistance is cut into three equal parts, then
Resistance of each part `= (90)/(3) = 30 Omega`
When the three resistors are connected in parallel then, resistance of a combination,
`(1)/( R) = (1)/( 30) + (1)/( 30) + (1)/( 30) = (1+ 1+ 1)/( 30) = (3)/( 30) = (1)/ (10) therefore R = 10 Omega`