8/14/2019 Exam Obj EEC 242

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8/14/2019 Exam Obj EEC 242

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A B

Reactive power=Average power Apparent power=reactive power

V1 lags V2 by 2 V1 lags V2 by .

1002 V 200

100 V, 100 Hz 100 V, 50 Hz

50H 1H

minimum maximumis in phase with emf lags the emf by 90 o

zero leading

12 20

220V,60W 220V,100W

110V 120V

0.707W 45

440W 220W

inductive load capacitive load

12.5A 17.68A

120W 0W

1 45

KW KVAR

S = Vrms*Irms (S/Real power)= power factor

0 1

a linear growth a linear decay

inductor capacitor

inductor capacitor

8s 2s

8s 2s

25K 2.5K0.25s 1s

Natural state steady state

short ciruit open circuit

electric field magnetic field

381V 311V

58V 173V

Line voltage = phase voltage Line current = Phase current

Line voltage = phase current Line current = Phase current

balanced unbalanced

11.25H 22.5H

0.1875 0.75

tranducer transformer

mutual inductance magnetically coupled

mutual inductance self inductance

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C D ANSWER marks

power factor is maximum voltage = current C 1.5

V2 lags V1 by V1 leads V2 by B 1.5100 2002 A 1.5

1002 V, 100 Hz 502 V, 100 Hz A 1.510H 100H A 1.5

1 non of the above D 1.5lags the emf by 90 o leads the emf by 90 o C 1.5

lagging unity D 1.5

16 8 C 1.5

115V,60W 115V,100W D 1.5

170V 84.8V C 1.5

0.71 -0.71 C 1.5

110W 110VA B 1.5

resistive load resonating load B 1.5

8.8A 25A B 1.5

240W 120VA B 1.5

0.707 -0.707 C 1.5

KVA KWh C 1.5

S = (VmIm)/2 Scos = Average power B 1.5

90 non of the above D 1.5

an exponential decay an exponential growth D 1.5

resistor all of the above A 1.5

resistor all of the above B 1.5

40s 20s C 1.5

0.5 s 10s B 1.5

125k 12.5K A 1.55s 25s B 1.5

transient state normal state B 1.5

neither of the above transient circuit B 1.5

electromotive field inductive field B 1.5

127V 156V C 1.5

100V 71V C 1.5

Line current = 3 phase current non of the above B 1.5

Line current = 1/3 phase voltage Line current = 3 phase current D 1.5

unidentical identical B 1.5

5.625H 6H A 1.5

1.333 12 B 1.5

capacitor inductor B 1.5

conductively coupled self inductance C 1.5

magnetically coupled self reactance B 1.5

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Time

60minutes