Aashish Ingle India

Three resistance of 15Ω each are connected in delta. The resistance of equivalent star will have a value of

(a) 12Ω
(b) 5Ω
(c) 5/3Ω
(d) 45Ω

Ans. (b) 5Ω 

A source is delivering maximum power to a resistance through a network. The ratio of power delivered to the source power

(a) is always 0.5
(b) may be 0.5 or less
(c) may be 0.5 or less or more
(d) may be 0.5 or more

Ans. (b) may be 0.5 or less 

Two capacitors of 1 μF and 2 μF are connected in series across a 30 V dc battery. After the capacitors have been charged, the charges across the two capacitors will be____.

(a) 10 μC each
(b) 20 μC each
(c) 10 μC and 20 μC
(d) 20 μC and 10 μC

Ans.  (b) 20 μC each

Two capacitors of 1 μF and 2μF capacitance are connected in parallel across a 30 V dc battery. After the capacitors have bean charged, the charges across the two capacitors will be____.


(a) 30 μC each
(b) 60 μC each
(c) 30 μC and 60 μC respectively
(d) 60 μC and 30 μC respectively


Ans. (c) 30 μC and 60 μC respectively 

Two capacitor each of capacitance C and breakdown voltage V are joined in series. The capacitance and breakdown voltage of the combination is


(a) 0.5 C and 2 V
(b) 0.5 C and 0.5 V
(c) C and V
(d) 2 C and 2 V

Ans. (a) 0.5 C and 2 V 

The correct relation between energy and charge is


(a) Energy = voltage / charge
(b) Charge = Energy x voltage
(c) Energy = voltage (charge)0.5
(d) Energy = voltage x charge

Ans. (b) Charge = Energy x voltage

One coulomb charge is equal to the charge on.

(a) 6.24 x 1018 electrons
(b) 6.24 x 1024 electrons
(c) 6.24 x 1018 atoms
(d) none of the above

Ans. (a) 6.24 x 1018 electrons 

The condition, that a 2-port network is reciprocal, can be expressed in terms of its ABCD parameters as…….

Ans.   AD – BC = 1

For a 2-port network to be reciprocal,


(a) z11 = z22
(b) y21 = y12
(c) h21 = -h12
(d) AD – BC = 0

Aans. (b) y21 = y12 & (c) h21 = -h12 

Two Two-port networks are connected in cascade. The combination is to the represented as a single two – port network, by multiplying the individual


(a) z-parameter matrices
(b) h-parameter matrices
(c) y-parameter matrices
(d) ABCD parameter

Ans. (d) ABCD parameter

The current, i(t), through a 10-Ω resistor in series with an inductance, is given by i(t) = 3 + 4 sin (100 t + 450 ) + 4 sin (300 t + 600 ) amperes. The RMS value of the current and the power dissipated in the circuit are:


(a) √41A, 410 W, respectively
(b) √35 A, 350 W, respectively
(c) 5 A, 250 W, respectively
(d) 11 A, 1210 W respectively

Ans.   5 A, 250 W, respectively 

Consider a DC voltage source connected to a series R-C circuit. When the steady state reaches, the ratio of the energy stored in the capacitor to the total energy supplied by the voltage source, is equal to ________.

(a) 0.362
(b) 0.500
(c) 0.632
(d) 1.000


Ans.  (b) 0.500

A DC voltage source is connected across a series R-L-C circuit. Under steady state conditions, the applied DC voltage drops entirely across the

(a) R only
(b) L only
(c) C only
(d) R and L combination

Ans. (c) C only 

A series LCR circuit consisting of 𝑅 = 10 Ω, |𝑋𝐿 | = 20 Ω 𝑎𝑛𝑑 |𝑋𝐶 | = 20 Ω is connected across an a.c. supply of 200 V rms. The rms voltage across the capacitor is....

(a) 200∠ − 900 𝑉
(b) 200∠ + 900 𝑉
(c) 400∠ + 900 𝑉
(d) 400∠ − 900 V

Ans. (d) 400∠ − 900 V

A load, ZL=RL+jXL is to be matched, using an ideal transformer, to a generator of internal impedance, ZS=RS+jXS . The turns ration of the transformer required is

(a) √|𝑍𝐿/𝑍𝑆 |
(b) √|𝑅𝐿/𝑅𝑆 |
(c) √|𝑅𝐿/𝑍𝑆 |
(d) √|𝑍𝐿/𝑅𝑆 |

Ans.  (a)  √|𝑍𝐿/𝑍𝑆 |

If an impedance ZL is connected across a voltage source V with source impedance ZS’ then for maximum power transfer, the load impedance must be equal to.....

1. source impedance ZS
2. real part of ZS
3. complex conjugate of ZS
4. imaginary part of ZS