Figure I shows an experimental setup to be used in identifying the value of unknown resister, R. Internal resistance of Voltmeter is 0.5 kn. Observations are as follows, Voltmeter Reading - 100 V Ammeter Reading-12 A III IV. 1 Calculate the resistance using meter readings. II Calculate the percentage error of the above method if the exact value of the resistance is 4.50. V VII .1 R IL III. IV. V A VL Briefly explain how the Loss of Charge Method can be used to measure unknown resistance. A resistor is connected in parallel with a capacitor of 0.22 F and it is allowed to charge to a voltage of 400 V. After the supply is disconnected, it is found that the terminal voltage falls to 250 V in 90 seconds. Calculate the value of the unknown resistor assuming that the capacitor does not possess any leakage V Briefly describe the most probable reason for having such a value for error percentage Suggest a modification to the above circuit to minimize the error percentage. Calculate the new value of error percentage for the circuit you have suggested. Later, the unknown resistor, R was measured using a Kelvin Double Bridge circuit. Draw the circuit diagram and derive an expression to determine R, if the outer ratio and the inner ratio are equal. Calculate the unknown resistance if the standard resistance is 0.471 Q and the outer ratio is 10. Question 2 L Describe the method of increasing the voltage measuring range of a DC potentiometer using volt-ratio box. Page 1 ii. Illustrate how the DC potentiometer can be used to calibrate a wattmeter. Describe the method of measuring unknown impedance using the AC potentiometer Illustrate the principle of accuracy increasing of an AC potentiometer using Kelvin- Varley slide wire. Draw a connection diagram to illustrate how potential transformer and current transformer are used to measure voltage, current, power and energy in a high power application. Question 3 L What is the "Equivalent Series Resistance (ESR) regarding capacitor modelling? 11. Draw the circuit diagram of "Modified De Sauty's Bridge' and derive an expression for the unknown capacitor and resistance. III. Explain why De Sauty's bridge needs a modification to measure capacitors with losses Sketch the circuit diagram of Schering Bridge and derive the expressions for capacitance and loss factor at balance condition. IV. Explain with equations how the Schering Bridge can be used as an method of calculating permittivity of a specimen. Page 2