# Star-Delta Transformation MCQ’s

This set of Network Theory Multiple Choice Questions & Answers (MCQs) focuses on “Star-Delta Transformation”.

1. If a resistor R_{x} is connected between nodes X and Y, R_{y} between X and Y, R_{z} between Y and Z to form a delta connection, then after transformation to star, the resistance at node Y is?

a) R_{z}R_{y}/(R_{x}+R_{y}+R_{z})

b) R_{z}R_{x}/(R_{x}+R_{y}+R_{z})

c) R_{x}R_{y}/(R_{x}+R_{y}+R_{z})

d) (R_{z}+R_{y})/(R_{x}+R_{y}+R_{z})

2. If a resistor R_{x} is connected between nodes X and Y, R_{y} between X and Y, R_{z} between Y and Z to form a delta connection, then after transformation to star, the resistance at node Z is?

a) R_{y}R_{x}/(R_{x}+R_{y}+R_{z})

b) R_{y}R_{x}/(R_{x}+R_{y}+R_{z})

c) R_{z}R_{y}/(R_{x}+R_{y}+R_{z})

d) (R_{z}+R_{x})/(R_{x}+R_{y}+R_{z})

3. If a resistor R_{x} is connected between nodes X and Y, R_{y} between X and Y, R_{z} between Y and Z to form a delta connection, then after transformation to star, the resistor at node X is?

a) R_{x}R_{y}/(R_{x}+R_{y}+R_{z})

b) R_{x}R_{z}/(R_{x}+R_{y}+R_{z})

c) R_{z}R_{y}/(R_{x}+R_{y}+R_{z})

d) (R_{x}+R_{y})/(R_{x}+R_{y}+R_{z})

4. If the resistors of star connected system are R_{1}, R_{2}, R_{3} then the resistance between 1 and 2 in delta connected system will be?

a) (R_{1}R_{2} + R_{2}R_{3} + R_{3}R_{1})/R_{3}

b) (R_{1}R_{2} + R_{2}R_{3} + R_{3}R_{1})/R_{1}

c) (R_{1}R_{2} + R_{2}R_{3} + R_{3}R_{1})/R_{2}

d) (R_{1}R_{2} + R_{2}R_{3} + R_{3}R_{1})/(R_{1}+R_{2})

5. If the resistors of star connected system are R_{1}, R_{2}, R_{3} then the resistance between 3 and 1 in delta connected system will be?

a) (R_{1}R_{2} + R_{2}R_{3} + R_{3}R_{1})/R_{1}

b) (R_{1}R_{2} + R_{2}R_{3} + R_{3}R_{1})/R_{3}

c) (R_{1}R_{2} + R_{2}R_{3} + R_{3}R_{1})/R_{2}

d) (R_{1}R_{2} + R_{2}R_{3} + R_{3}R_{1})/(R_{3}+R_{1})

6. Find the equivalent resistance at node C in the delta connected circuit shown below.

a) 3.66

b) 4.66

c) 5.66

d) 6.66

7. If the resistors of star connected system are R_{1}, R_{2}, R_{3} then the resistance between 2 and 3 in delta connected system will be?

a) (R_{1}R_{2} + R_{2}R_{3} + R_{3}R_{1})/R_{3}

b) (R_{1}R_{2} + R_{2}R_{3} + R_{3}R_{1})/R_{2}

c) (R_{1}R_{2} + R_{2}R_{3} + R_{3}R_{1})/R_{1}

d) (R_{1}R_{2} + R_{2}R_{3} + R_{3}R_{1})/(R_{3}+R_{2})

8. Find the equivalent resistance at node A in the delta connected circuit shown in the figure below.

a) 1

b) 2

c) 3

d) 4

9. Find the equivalent resistance between node 1 and node 3 in the star connected circuit shown below.

a) 30

b) 31

c) 32

d) 33

10. Find the equivalent resistance between node 1 and node 2 in the star connected circuit shown below.

a) 2

b) 29

c) 30

d) 31

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