GATE EE 2004 Electrical Circuits Q 4 - Grad Plus
GATE EE 2004 Electrical Circuits Q 4

GATE EE 2004 Electrical Circuits Q 4

In figure, Ra, Rb and Rc are 20Ω, 10Ω, and 10Ω respectively. The resistances R1, R2 and R3 in Ω of n equivalent star-connection are

a)2.5, 5, 5

b)5, 2.5, 5

c) 5, 5, 2.5

d) 2.5, 5, 2.5

Ans.(a)

Explanation:

Applying star to delta to conversin

Ra = 20Ω; Rb =10Ω and Rc =10 Ω

R_1\;=\frac{R_{b\;}\;R_c}{R_a+\;R_b+\;R_c} =\frac{10\times10}{20+10+10}

=2.5Ω

R_2=\frac{R_c\;R_a}{R_a\;+R_b+\;R_c} =\frac{10\times20}{20+10+10}

= 5 Ω

\;R_{3\;}=\frac{R_a\;R_b}{R_a\;+R_b+\;R_c} =\frac{20\times10}{20+10+10}

= 5 Ω

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