**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.

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

30 amps, will be

A [v])

42.4sin50πt.

42.4sin50πt.

B [ ]) 30sin50πt.

C [ ]) 30sin25πt.

D [ ])

42.4sin25πt.

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.

= 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

considered to be connected in

A [v]) series.

B [ ]) parallel.

C [ ]) either

parallel or series.

parallel or series.

D [ ]) none of the

above.

above.

**3) R1 = 36 Ω and R2 = 75 Ω, each having tolerance of ±5% are**

connected in series. The value of resultant resistance is

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

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.

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.

constant.

D [ ]) increases

exponentially.

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

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

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

one

A [ ]) resistor.

B [v]) voltage

source .

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.

source.

C [ ]) current

source

source

D [ ]) battery.

**9) terminal voltage is equal to the source emf.**

A [ ]) terminal

voltage can not exceed source emf.

voltage can not exceed source emf.

B [v]) terminal

voltage is always lower than source emf.

voltage is always lower than source emf.

C [ ]) terminal

voltage is higher than the source emf.

voltage is higher than the source emf.

D [ ]) terminal

voltage is equal to the source emf.

voltage is equal to the source emf.

**10) To neglect a voltage source, the terminals across the source are**

A [ ]) open

circuited.

circuited.

B [ V]) short

circuited.

circuited.

C [ ]) replaced by

some resistance.

some resistance.

D [ ]) replaced by

inductor.

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

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.

four lines.

D [v]) not

changed.

changed.

**12) A practical current source is represented by**

A [ ]) a

resistance in series with an ideal current source.

resistance in series with an ideal current source.

B [v]) a

resistance in parallel with an ideal current source.

resistance in parallel with an ideal current source.

C [ ]) a

resistance in parallel with an ideal voltage source.

resistance in parallel with an ideal voltage source.

D [ ]) none of

above.

above.

**13) Constant voltage source is**

A [ ]) active and

bilateral.

bilateral.

B [ ]) passive and

bilateral.

bilateral.

C [v]) active and

unilateral.

unilateral.

D [ ]) passive and

unilateral.

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.

these.

E [ ])

HINTS-Total power consumed = x² X 2 + 2²/2 ∴ 10 W = 2x² + 2 Therefore, x = 2 A.

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.

Regenerative.

B [ ]) Dynamic.

C [ ]) Plugging.

D [ ]) None of

these.

these.

**16) Our household apparatus are connected in**

A [v]) parallel.

B [ ]) series.

C [ ]) cascade.

D [ ]) series and

parallel combination.

parallel combination.

**17) In a delta network each element**

has value R. The value of each element in equivalent star network will be

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.

networks.

B [ ]) non planar

networks.

networks.

C [v]) both

planner and non planner networks.

planner and non planner networks.

D [ ]) neither

planner nor non planner networks.

planner nor non planner networks.

**19) Mesh analysis is applicable for**

A [v]) planar

networks

networks

B [ ]) non

planarnetworks

planarnetworks

C [ ]) both

planner and non planner networks.

planner and non planner networks.

D [ ]) neither

planner nor non planner networks.

planner nor non planner networks.

**20) KCL works on the principle of which of the following**

A [v]) Law of

conservation of charge

conservation of charge

B [ ]) Law of

conservation of energy

conservation of energy

C [ ]) both

D [ ]) None of

these

these

sir…u r doing a tremendous job.i want to know one thing that the question which u have given in online test and 200 expected question are ever asked in bsnl exam …because i have to a much previous year paper so i cant guess.if yes then solving these question give me much more confident.thanks alot sir

thanks for appreciation and near about 50-60 percentage have asked and 30 percentage is based on previous exam questions pattern and 10 percentage is new,it will surely help you.