Question

three resistors r1,r2 are should be connected such that to get the least resistance with the resistance of then respectively 40ohms and 120ohms and if another resistor connected them in parallel with the value of 70ohms fond the equivalent resistance of the circuit

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Answer 1

Answer:

21ohms

Explanation:

To get the least resistance the resistance should be connected in parallel.

R'= (r1*r2)/r1+r2

R'= 30ohms

This is then connected to 70 ohms in parallel

Therefore , equivalence resistance (R) :

R= (R'*70)/R'+70

R=21ohms