100 PROBLEMS IN ELECTRICAL ENGINEERING – PART – 12 – FIVE PROBLEMS ON KIRCHHOFF’S VOLTAGE LAW

KIRCHHOFF’S LAW

In a closed electrical circuit the sum of the potential drops is equal to the sum of the potential raises.

PROBLEM – 01

Three lamps A, B and C takes 0.7, 0.8 and 0.9 amps respectively. When they are connected across 110 V supply. Calculate the value of current when they are connected in series across 220 V supply. Assuming filament resistances to remain unaltered. Find the voltage across each lamp.

PROBLEM – 02

Four resistors and two voltage sources are connected as shown in figure. Find the voltage drop across each resistance.

PROBLEM – 03

Six resistors and one voltage source are connected as shown in figure. Find the current flow through the one ohm resistor and verify Kirchhoff’s voltage law.

PROBLEM – 04

Seven resistors and one voltage source are connected as shown in figure. Voltage across Vab is zero. Find the value of X and verify Kirchhoff’s voltage law.

PROBLEM – 05

A 60 W, 220 V bulb and 200 W, 220 V bulb are connected in series across a 440 V DC supply. (i) Find voltage across each bulb and (ii) Determine the value R3 to be connected in parallel with a 60 W bulb to ensure equal sharing of voltage.