BSNL TTA Basic Electricity MCQ

Attempt Free BSNL TTA Basic Electricity MCQ Here. Read The Important BSNL MCQ From Below.

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 [ ]) 1.1
E [ ]) HINTS-form factor=rms value /average value=0.707/0.637=1.11

BSNL TTA Basic Electricity MCQ

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.

BSNL TTA Basic Electricity MCQ

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.

BSNL TTA Basic Electricity MCQ

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.

BSNL TTA Basic Electricity MCQ

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