Explore topic-wise MCQs in Network Theory.

This section includes 8 Mcqs, each offering curated multiple-choice questions to sharpen your Network Theory knowledge and support exam preparation. Choose a topic below to get started.

1.

If a star connected system has equal impedances Z1, then after converting into delta connected system having equal impedances Z2, then?

A. Z<sub>2</sub> = Z<sub>1</sub>
B. Z<sub>2</sub> = 2Z<sub>1</sub>
C. Z<sub>2</sub> = 3Z<sub>1</sub>
D. Z<sub>2</sub> = 4Z<sub>1</sub>
Answer» D. Z<sub>2</sub> = 4Z<sub>1</sub>
Discussion
2.

A symmetrical three-phase, three-wire 440V supply is connected to star-connected load. The impedances in each branch are ZR = (2+j3) , ZY = (1-j2) , ZB = (3+j4) . Find ZBR.

A. (5.22-j0.82)
B. (-3.02+j8)
C. (-5.22+j0.82)
D. (3.8-j0.38)
Answer» C. (-5.22+j0.82)
Discussion
3.

A symmetrical three-phase, three-wire 440V supply is connected to star-connected load. The impedances in each branch are ZR = (2+j3) , ZY = (1-j2) , ZB = (3+j4) . Find ZBY.

A. (-5.22+j0.82)
B. (5.22-j0.82)
C. (3.8-j0.38)
D. (-3.02+j8)
Answer» C. (3.8-j0.38)
Discussion
4.

A symmetrical three-phase, three-wire 440V supply is connected to star-connected load. The impedances in each branch are ZR = (2+j3) , ZY = (1-j2) , ZB = (3+j4) . Find ZRY.

A. (5.22-j0.82)
B. (-3.02+j8)
C. (3.8-j0.38)
D. (-5.22+j0.82)
Answer» D. (-5.22+j0.82)
Discussion
5.

If the resistors of star connected system are ZR, ZY, ZB then the impedance ZBR in delta connected system will be?

A. (Z<sub>R</sub>Z<sub>Y</sub> + Z<sub>Y</sub>Z<sub>B</sub> + Z<sub>B</sub>Z<sub>R</sub>)/Z<sub>Y</sub>
B. (Z<sub>R</sub>Z<sub>Y</sub> + Z<sub>Y</sub>Z<sub>B</sub> + Z<sub>B</sub>Z<sub>R</sub>)/<sub>R</sub>
C. (Z<sub>R</sub>Z<sub>Y</sub> + Z<sub>Y</sub>Z<sub>B</sub> + Z<sub>B</sub>Z<sub>R</sub>)/Z<sub>B</sub>
D. (Z<sub>R</sub>Z<sub>Y</sub> + Z<sub>Y</sub>Z<sub>B</sub> + Z<sub>B</sub>Z<sub>R</sub>)/(Z<sub>B</sub>+Z<sub>R</sub>)
Answer» B. (Z<sub>R</sub>Z<sub>Y</sub> + Z<sub>Y</sub>Z<sub>B</sub> + Z<sub>B</sub>Z<sub>R</sub>)/<sub>R</sub>
Discussion
6.

If the resistors of star connected system are ZR, ZY, ZB then the impedance ZBY in delta connected system will be?

A. (Z<sub>R</sub>Z<sub>Y</sub> + Z<sub>Y</sub>Z<sub>B</sub> + Z<sub>B</sub>Z<sub>R</sub>)/(Z<sub>B</sub>+Z<sub>Y</sub>)
B. (Z<sub>R</sub>Z<sub>Y</sub> + Z<sub>Y</sub>Z<sub>B</sub> + Z<sub>B</sub>Z<sub>R</sub>)/Z<sub>B</sub>
C. (Z<sub>R</sub>Z<sub>Y</sub> + Z<sub>Y</sub>Z<sub>B</sub> + Z<sub>B</sub>Z<sub>R</sub>)/Z<sub>Y</sub>
D. (Z<sub>R</sub>Z<sub>Y</sub> + Z<sub>Y</sub>Z<sub>B</sub> + Z<sub>B</sub>Z<sub>R</sub>)/Z<sub>R</sub>
Answer» E.
Discussion
7.

If a resistor ZR is connected between R and N, ZBR between R and B, ZRY between R and Y and ZBY between B and Y form a delta connection, then after transformation to star, the impedance at B is?

A. (Z<sub>BR</sub>Z<sub>BY</sub>)/(Z<sub>RY</sub>+Z<sub>BY</sub>+Z<sub>BR</sub>)
B. (Z<sub>RY</sub>Z<sub>BY</sub>)/(Z<sub>RY</sub>+Z<sub>BY</sub>+Z<sub>BR</sub>)
C. (Z<sub>BY</sub>)/(Z<sub>RY</sub>+Z<sub>BY</sub>+Z<sub>BR</sub>)
D. (Z<sub>BR</sub>)/(Z<sub>RY</sub>+Z<sub>BY</sub>+Z<sub>BR</sub>)
Answer» B. (Z<sub>RY</sub>Z<sub>BY</sub>)/(Z<sub>RY</sub>+Z<sub>BY</sub>+Z<sub>BR</sub>)
Discussion
8.

If a resistor ZR is connected between R and N, ZBR between R and B, ZRY between R and Y and ZBY between B and Y form a delta connection, then after transformation to star, the impedance at Y is?

A. (Z<sub>RY</sub>)/(Z<sub>RY</sub>+Z<sub>BY</sub>+Z<sub>BR</sub>)
B. (Z<sub>BY</sub>)/(Z<sub>RY</sub>+Z<sub>BY</sub>+Z<sub>BR</sub>)
C. (Z<sub>RY</sub>Z<sub>BY</sub>)/(Z<sub>RY</sub>+Z<sub>BY</sub>+Z<sub>BR</sub>)
D. (Z<sub>RY</sub>Z<sub>BR</sub>)/(Z<sub>RY</sub>+Z<sub>BY</sub>+Z<sub>BR</sub>)
Answer» D. (Z<sub>RY</sub>Z<sub>BR</sub>)/(Z<sub>RY</sub>+Z<sub>BY</sub>+Z<sub>BR</sub>)
Discussion