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Q6. In the network shown in Fig Q1, the meter indicates 2 mA in the direction shown.

Determine EACH of the following:

(a) The resistance of the meter;

(b) The reading on the meter if the 1.5 kΩ and the 2 kΩ resistors are interchanged.

Q7. A non-linear resistor whose characteristic is given by:

l (mA) = 0.1 V²

Is connected in series with a resistor of 680 Ω to a 16 V d.c. supply. Determine EACH of the following:

(a) The value of the voltage across each element;

(b) The circuit current;

(c) The value to which the linear resistance must be changed to give equal voltages across the two elements;

(d) The circuit current for the condition in Q2(c).

Q6. In the two-stage voltage amplifier shown in Fig Q3, both the npn and pnp transistors have high current gains and their leakage currents may be neglected. Transistor T₁ has a base-emitter volt drop of 0.7 V and transistor T₂ has a base emitter drop of 0.3 V. Calculate EACH of the following:

(a) The voltage between the collector and emitter for each transistor;

(b) The power dissipated in each transistor.

Q5. A 440 V /110 V single phase step down transformer is rated at 60 kV A full load output. The iron loss is 4 kW and the copper loss at full load is 6 kW. Calculate EACH of the following:

(a) The kVA output at which maximum efficiency will be achieved;

(b) The efficiency at 50 kW output and 0.85 p.f.

Q6. Three identical coils each of inductance 0.1 H and resistance 30Ω are connected in delta to a three phase three wire supply of 440 V 50 Hz. Three identical capacitors connected in star are now joined to the same supply to raise the overall power factor to 0.9 lag.

Calculate EACH of the following:

(a) The value of each capacitor;

(b) The percentage reduction in line current;

(c) The kVA taken by the capacitors.