Three unequal resistor in parallel are equivalent to a resistance `1Omega` If two of them are in the ratio 1:2 and if no resistance value is fractional the largest of the three resistance in ohm is

Options

A. 4
B. 6
C. 8
D. 12

Answer

D

Explanation

Potential difference without voltmeter `V_1 = 400xx(6)/(400)+(800)`
`V_1 = 2.000 Vol t`
The resistance of the circuit with voltmeter is
`R_(eq) = [ (10000xx400)/(10000+400)] +800 = 1184.615`
Potential difference across `400Omega` resistance with voltmeter is
`V_2 = 6-800 ((6)/(1184.615))= 1.948V`
Error in measurment of potential difference is , `Delta V = V_1`
`Delta V= 2-1.948= 0.052`