1. 12 V source with polarities positive
top and negative down, is connected to a circuit consist of only
resistors. I and P are the current and power for the voltage source,
then which one of the following is true?
A) I >= 0 && P >= 0
C) I < 0 && P > 0
B) I > 0 && P < 0
D) I > 0 && P > 0
Answer : [D] I > 0 && P >
0
2.
Assertion (A): When two elements are
connected in parallel, then voltage Across each element is same.
Reason (R): In a loop the sum of all
voltage drops should be equal to sum Of all voltage rises.
a) Both A & R are correct, but R is
not correct explanation for A.
b) Both A & R are correct, and R is
the correct explanation for A.
c) Both A & R are incorrect.
d) A is correct but R is incorrect.
Answer : [b] Both A & R are
correct, and R is the correct explanation for A.
3. 20 A source with the current
direction upward, is connected to a circuit consist of only
resistors. V and P are the voltage and power for the current source,
and then which one of the following is true?
A) V >= 0 && P >= 0
C) V < 0 && P > 0
B) V > 0 && P < 0
D) V > 0 && P > 0
Answer : [D] V > 0 && P >
0
4. In a particular lab experiment, one
student was allowed to measure a voltage across an ideal voltage
source of magnitude 10 V. Instead of connecting a voltmeter that
student connected an ammeter (internal resistance 2 Ω, 4 A fuse)
across the terminals of voltage source. Now, what was the reading
observed by the student?
A) 10 V
B) 9 V
C) 5 V
D) Fuse was burn out
Answer : [D] Fuse was burn out
5. Consider the following two cases.
Case (I): A 60 Watt bulb connected
across a 100 V d.c.
Case (II): Two bulbs of each 60 Watt
connected in series across a 100 V d.c.
Which one of the following is true?
1. Intensity is more in case (I)
2. Power consumption is less in case
(I)
3. Intensity is more in case (II)
4. Power consumption is less in case
(II)
A) 1 and 2
B) 2 and 3
c) 3 and 4
D) 1 and 4
Answer : [D] 1 and 4
6. Consider the following two cases.
Case (I): A 60 Watt bulb connected
across a 100 V d.c.
Case (II): Two bulbs of each 60 Watt
connected in parallel across a 100 V d.c.
Which one of the following is true?
1. Intensity is same in both the cases
2. Power consumption is less in case
(I)
3. Intensity is more in case (II)
4. Power consumption is less in case
(II)
A) 1 and 2
B) 2 and 3
c) 3 and 4
D) 1 and 4
Answer : [A] 1 and 2
7. Match the following
Column A Column B
(i) Inductive load (P) positive
impedence angle
(ii) Capacitive load (Q) negative
impedence angle
(iii) Reactive power Q>0 (R)
for inductive load
(iv) Reactive power Q<0 (S) for
capacitive load
(v)Power factor of a pure inductor
(T) 0
(U) 1
(A) (i) – Q, (ii) – P, (iii) – S,
(iv) – R, (v) -U
(B) (i) – P, (ii) – Q, (iii) – R,
(iv) – S, (v) - T
(C) (i) – Q, (ii) – P, (iii) – S,
(iv) – R, (v) - T
(D) (i) – P, (ii) – Q, (iii) – R,
(iv) – S, (v) – U
Answer : [A] (i) – Q, (ii) – P,
(iii) – S, (iv) – R, (v) -U
8. The lagging power factor of 50 KVA
load is improved from 0.8 to 0.95 without changing its apparent power
rating. Which of the following represents the appropriate combination
of the real and reactive powers of the load under the improved power
factor?
(A) P=40 KW, Q=30 KVAR
(B) P=40 KW, Q=15.6 KVAR
(C) P= 47.5 KW, Q=30 KVAR
(D) P= 47.5 KW, Q=15.6 KVAR
Answer : [D] P= 47.5 KW, Q=15.6 KVAR
9. For a lagging power factor complex
load S=P+j*Q, with Q>0, which of the following is not true
representation of the reactive power. Sqrt refers to square root of
and pf refers to power factor
(A) Q= P* sqrt {(1/pf2)-1}
(B) Q= -P* sqrt {(1/pf2)-1}
(C) Q= P Tan {cos-1 (pf)}
(D) Q= S sin {cos-1 (pf)}
Answer : [B] Q= -P* sqrt {(1/pf2)-1}
10. For a RL circuit which one of the
following is correct
(A) 0<powerfactor<1
(B) current leads
(C) unity power factor
(D) zero power factor
Answer : [A] 0<powerfactor<1
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