# Recent questions and answers in Electrical Engineering

The following circuit has following parameters. Ac=Ag=9cm2 g=30cm N=500 Meur=70000 Find the Inductance of the coil

Three lamps are connected in parallel across a 120 Volt source. If one lamp burns out, the remaining two will be: A. Glow dimmer B. Glow brighter C. Not light D. Glow with the same brightness as before

The measurement of dielectric loss and power factor is done using  (A) Weins Bridge (B) Hays Bridge (C) Schering Bridge (D) Wheat Stone Bridge

An Auto-transformer (which has only one winding) may be used as a ______ .  (A) Both Step-Up and Step-Down transformer (B) Step-Down Transformer (C) Step-Up Transformer (D) None of these

Three resistors of 4 Ω, 6 Ω and 9 Ω are connected in parallel. Which resistor consumes the maximum power?  (A) 4 Ω (B) 6 Ω (C) 9 Ω (D) 17 Ω

Two's complement of -8 is  (A) 1000 (B) 1010 (C) 110 (D) 1110

The cycle time of a PLC is the time it takes to   (a) read all the input signals. (b) read all the input signals, run the program and update outputs. (c) read an input signal. (d) check all the input signals against the program.

Mho relay is   (a) current restrained current relay. (b) voltage restrained directional relay. (c) current restrained directional relay. (d) voltage restrained current relay.

What happens to the resistance of a wire when its length as well as the cross-sectional area are doubled? A) It doubles B) It becomes 4 times C) It becomes 2π times D) It remains the same

What is the flow of electrons from one atom to another called?

What is the difference between eddy current and hysteresis loss?

In a pure inductive circuit?

Magnitude of current at resonance in R-L-C circuit?

The power factor at resonance in R-L- C parallel circuit is?

Pure inductive circuit takes power from the A.C. line when?

The voltage phasor of a circuit is 10 ∠15° V and the current phasor is 2∠–45° A. The active and reactive powers in the circuit are   (a) 20 2 W and 10 2 VAR (b) 10 W and 10 3 VAR (c) 5 W and 5 3 VAR (d) 10 3 W and – 10 VAR

Do electrons flow from the anode to the cathode?

If a positively charged body is placed inside a spherical hollow conductor, what will be the polarity of charge inside and outside the hollow conductor ? (a) Inside positive, outside negative (b) Inside negative, outside positive (c) Both negative (d) Both positive

what is voltage?

why the electrical appliances are connected in parallel ?

what is current?

what is lightning arrester?

What type of excitation is given to the rotor winding of a synchronous motor?  (A) DC supply at 100 -250 V (B) AC supply at 400 V (C) Revolving field (D) Induction from stator currents

A 60 Hz, 4 pole turbo generator rated 100 MVA, 13.8 KV has an inertia constant of 10 MJ/MVA. Find the stored energy in the rotor at synchronous speed.  (A) 10 MJ (B) 100 J (C) 1000 J (D) 1000 MJ

The maximum demand of consumer is 2 kW and his daily energy consumption is 20 units. Its Load Factor is (1) 10.15% (2) 41.6 % (3) 50 % (4) 60%

A heater takes 4 Amp at 250 volts. How much power does it consume? A. 1 KWatt B. 2 KWatt C. 3 KWatt D. 4 KWatt

A network has 10 nodes and 17 branches. The number of independent mesh equations required to solve the network is   (a) 7 (b) 8 (c) 10 (d) 45

Horizontal axis and vertical axis are the types of   (a) Nuclear Reactor (b) Wind Mills (c) Bio Gas Reactor (d) Solar Cell

What does Fleming's left hand rule state?

Moving iron instruments can be used for measuring (1) Direct currents and voltages (2) Radio frequency currents (3) A.C currents and voltages (4) Both (a) and (c)

The core of a transformer (medium size) uses to provide high flux densities (a) diamagnetic (c) ferromagnetic core (b) paramagnetic (d) none of these

What is Data Acquisition System (DAS) ?

what is variable frequency drive ?

The equation of 50 Hz current sine wave having r.m.s. value of 60 A is?

The r.m.s. value of pure cosine function is?

Do cell phones use AC or DC current?

Why do we use AC current in our homes?

What is the direction of the flow of electrons?

What is the direction of flow of electric current in an electric circuit?

Write short notes on 3 phase AC system.

A 50Ω transmission line is terminated in an impedance of 20-j50. What will be the reflection coefficient? A) 0.69 B) 1.69 C) 6.9 D) 16.9

What is the value of susceptibility in case of vacuum? A) 1 B) 0.5 C) ∞ D) 0

The magnetic susceptibility of paramagnetic material is: A) Less than zero B) Less than one but positive C) Greater than one D) Equal to zero