# BSNL TTA (JE) BASIC ELECTRICITY 200 EXPECTED QUESTIONS PART TWO

NOTE-NO OF QUESTIONS-135
ANSWER KEY-Correct answer is indicated by symbol (V) in options.
HINTS-In some questions options E-HINTS is indicating the hints of answer.

SAMPLE QUESTIONS AND ANSWER

1) The equation for 25 cycles current sine wave having rms value of
30 amps, will be
A [v])
42.4sin50πt.
B [ ]) 30sin50πt.
C [ ]) 30sin25πt.
D [ ])
42.4sin25πt.
E [ ]) HINTS-Imsinωt = Imsin2πft.,Im = √2 X 30
= 42.4 A ,f is here 25 Hz ,equation will be 42.4sin2π25t = 42.4sin50πt.
2) The internal resistance of a practical voltage source is
considered to be connected in
A [v]) series.
B [ ]) parallel.
C [ ]) either
parallel or series.
D [ ]) none of the
above.
3) R1 = 36 Ω and R2 = 75 Ω, each having tolerance of ±5% are
connected in series. The value of resultant resistance is
A [ ]) 111 ± 0 Ω.
B [ ]) 111 ± 2.77
Ω. C [v]) 111 ± 5.55 Ω. D [ ]) 111 ± 7.23 Ω
E [ ])
HINTS-R1 = 36 ± 5% = 36 ± 1.8 Ω. R2 = 75 ± 5 % =75 ± 3.75 Ω. ∴ R1 + R2 = 111 ± 5.55 Ω.
4) The form factor of sinusoidal alternating current is
A [ ]) 0.
B [ ]) 1
C [v]) 1.11
D [ ]) 1.15

E [ ]) HINTS-form factor=rms value /average value=0.707/0.637=1.11

5) Whenever current is supplied by a source its terminal voltage
A [ ]) increases.
B [v]) decreases.
C [ ]) remains
constant.
D [ ]) increases
exponentially.
6) A current of 4 A flows in an AC
circuit when 100 V DC is applied to it whereas it takes 250 V AC to produce the
same current the power factor of the circuit is
A [v]) 0.4.
B [ ]) 10.
C [ ]) 1.
D [ ]) 0.85.
E [ ]) HINTS=FOR DC,R=V/I=100/4=25 Ohm FOR
AC,Z=V/I=250/4=62.5 Ohm
power factor cosφ=R/Z=25/62.5=0.4
7) A branch of a network is said to be active when it consists of
one
A [ ]) resistor.
B [v]) voltage
source .
C [ ]) inductor.
D [ ]) capacitor.
8) A branch of a network is said to be passive when it contains
A [v]) voltmeter.
B [ ]) voltage
source.
C [ ]) current
source
D [ ]) battery.
9) terminal voltage is equal to the source emf.
A [ ]) terminal
voltage can not exceed source emf.
B [v]) terminal
voltage is always lower than source emf.
C [ ]) terminal
voltage is higher than the source emf.
D [ ]) terminal
voltage is equal to the source emf.

10) To neglect a voltage source, the terminals across the source are
A [ ]) open
circuited.
B [ V]) short
circuited.
C [ ]) replaced by
some resistance.
D [ ]) replaced by
inductor.
11) A network consists of linear
resistors and ideal voltage source. If the value of resistors are doubled, then
voltage across each resistor is
A [ ]) halved.
B [ ]) doubled.
C [ ]) increased
four lines.
D [v]) not
changed.
12) A practical current source is represented by
A [ ]) a
resistance in series with an ideal current source.
B [v]) a
resistance in parallel with an ideal current source.
C [ ]) a
resistance in parallel with an ideal voltage source.
D [ ]) none of
above.
13) Constant voltage source is
A [ ]) active and
bilateral.
B [ ]) passive and
bilateral.
C [v]) active and
unilateral.
D [ ]) passive and
unilateral.
14) Total power consumed in the circuit below is 10 W. Find x.
A [ ]) 1 A.
B [v]) 2 A.
C [ ]) 3 A.
D [ ]) None of
these.

E [ ])
HINTS-Total power consumed = x² X 2 + 2²/2 ∴ 10 W = 2x² + 2 Therefore, x = 2 A.
15) In which braking back emf exceeds supply voltage?
A [v])
Regenerative.
B [ ]) Dynamic.
C [ ]) Plugging.
D [ ]) None of
these.
16) Our household apparatus are connected in
A [v]) parallel.
B [ ]) series.
C [ ]) cascade.
D [ ]) series and
parallel combination.
17) In a delta network each element
has value R. The value of each element in equivalent star network will be
A [ ]) R / 6
B [ ]) R / 4.
C [ ]) R / 2.
D [v]) R / 3.
18) Nodal analysis can be applied for
A [ ]) planar
networks.
B [ ]) non planar
networks.
C [v]) both
planner and non planner networks.
D [ ]) neither
planner nor non planner networks.
19) Mesh analysis is applicable for
A [v]) planar
networks
B [ ]) non
planarnetworks
C [ ]) both
planner and non planner networks.
D [ ]) neither
planner nor non planner networks.

20) KCL works on the principle of which of the following
A [v]) Law of
conservation of charge
B [ ]) Law of
conservation of energy
C [ ]) both
D [ ]) None of
these

1. Akansha Kesarwani September 10, 2016
• HARRY HOT04 September 10, 2016