# BEE GTU Paper Solution Winter 2021 | 311005

Here, We provide BEE GTU Paper Solution Winter 2021. Read the Full Basic Electrical Engineering gtu paper solution given below.

`BEE GTU Old Paper Winter 2021 [Marks : 70] : Click Here `

(a) Calculate current, resistance and energy consumed by an oven rated 230V,
1KW when used for 20 hours. Also calculate the electricity bill at the rate
of Rs. 7/- per unit.

To calculate the current, resistance, and energy consumed by the oven:

1. Current (I) = Power (P) / Voltage (V) = 1000W / 230V = 4.35A
2. Resistance (R) = Voltage (V) / Current (I) = 230V / 4.35A = 52.91Ω
3. Energy consumed (E) = Power (P) * Time (t) = 1000W * 20 hours = 20,000 Wh

To calculate the electricity bill:

1. Total energy consumed (E) = 20,000 Wh
2. Total number of units (U) = Energy (E) / 1000 = 20,000 / 1000 = 20 units
3. Total bill (B) = Total units (U) * Rate per unit (R) = 20 * 7 = 140 Rs

So, the electricity bill for 20 hours of usage at the rate of Rs. 7/- per unit would be 140 Rs.

(b) Define Power Factor. What are the disadvantages of Low Power Factor?

(c) Summarize; Mathematical & Waveform representation of an alternating
sinusoidal quantity (voltage or current). Demonstrate time period, peak
value, Peak to Peak value, Average value, RMS value. Write definition of
all.

(a) Write statement of Superposition, Norton and Thevenin theorem.

The superposition theorem states that in any linear network containing two or more
sources, the current in any element is equal to the algebraic sum of the current caused
by individual sources acting alone, while the other sources are inoperative.

Norton’s Theorem states that “Any linear circuit containing several energy sources and
resistances can be replaced by a single Constant Current generator in parallel with a
Single Resistor“.

Thevenin’s Theorem states that “Any linear circuit containing several voltages and
resistances can be replaced by just one single voltage in series with a single resistance connected across the load”.

(b) Write classification of Electric Networks.

(c) Write applications of Thevenin’s theorem. Find the current passing
through 2 Ω (Fig. A) resistance using Thevenin’s theorem. All resistances
are in Ω.

[OR] (c) Derive the expression for the rise of current in R-L series circuit when a
D.C. supply is switched on to it. Define time constant of it.

(a) Define Form factor. State the value of form factor for Sinusoidal
waveform.

Form factor is a term used in electrical engineering to describe the shape of a waveform, specifically the relationship between its average value and its peak value. It is a dimensionless quantity and is used to compare the waveform shapes of different signals.

The form factor of a sinusoidal waveform is defined as the ratio of the root-mean-square (RMS) value to the peak value:

Form factor (Kf) = RMS value / Peak value = √(2) / 2 = 0.707

The form factor of a sinusoidal waveform is a constant value and is equal to 0.707. This value is important in electrical engineering, as it is used to calculate the effective power in AC systems and to determine the required size of electrical components such as transformers and inductors.

(b) A series resonance network consisting of a resistor of 30Ω, a capacitor of
2μF and an inductor of 20mH is connected across a sinusoidal supply
voltage which has a constant output of 9 volts at all frequencies. Calculate,
the resonant frequency, the current at resonance, the voltage across the
inductor and capacitor at resonance, the Quality factor and the bandwidth
of the circuit.

(c) With the help of waveforms and phasor diagrams, comment on phase
relationship between voltage and current in single phase RLC series
circuit.

### OR

(a) Define Q-factor of RLC series circuit. What is the importance of it?

The Q-factor of an RLC series circuit is a dimensionless quantity that describes the damping of the circuit’s resonant response. It is defined as the ratio of the energy stored in the circuit to the energy lost per cycle due to resistance.

Q-factor = Energy stored in the circuit / Energy lost per cycle = X_L / R (where X_L is the reactance of the inductor)

###### The importance of the Q-factor in an RLC series circuit is that

it determines the circuit’s ability to store energy and its efficiency in resonant energy transfer. A higher Q-factor indicates that the circuit is more resonant and has a sharper frequency response, which can result in improved signal processing and filtering. A lower Q-factor, on the other hand, indicates that the circuit is less resonant and has a broader frequency response, which can result in improved stability and reduced susceptibility to external disturbances.

The Q-factor also determines the bandwidth of the circuit, which is the range of frequencies over which the circuit exhibits resonance. A higher Q-factor results in a narrower bandwidth, while a lower Q-factor results in a broader bandwidth.

(b) Draw Impedance triangle and Admittance triangle.

(c) A balanced 3-phase load consists of 3 coils each of resistance of 6 Ω and
inductive reactance of 8 Ω. Determine line current and power absorbed
when the coils are 1. Star connected and 2. Delta connected across 400V,
3-phase supply.

(a) State advantages of polyphase systems.

There are several advantages of polyphase systems over single phase systems, including:

• Increased power transfer capability
• Improved distribution efficiency
• Reduced voltage drop
• Reduced weight and size of equipment
• Improved reliability
• Improved power factor

(b) Mention Merits and Demerits of Induction Motor.

(c) Explain construction of single phase Transformer.

### OR

(a) Write applications of Auto Transformer.

Auto transformers are widely used in various applications due to their ability to provide high-efficiency voltage transformation with a compact design.

• Voltage regulation
• Motor starting
• Power factor correction
• High-voltage power distribution
• Audio and signal amplification

(b) Explain the principle of operation of an Alternator.

(c) Describe construction of a DC machine.

(a) Briefly explain block diagram of ELCB.

It is current operated device designed to operate when a leakage current exceeds the
predefined value.

It consists of a operating coil and a trip mechanism which operated the circuit when
required.

The coil is supplied through 1-Ф supply so current in phase & neutral wire will be same.

This current will produce flux linkages same in magnitude but of opposite direction. This
will result zero net flux in tripping coil of relay.

When fault or leakage current exceeds the limit higher current will flow in phase
conductor than neutral current.

Resultant flux now is out of balance in tripping coil of relay. Difference of flux will induce
emf in the coil which opens the contact of ELCB and isolate the circuit from the supply.

(b) Mention important points regarding Earthing of Electrical Installation.

(c) Write short technical notes on Battery Maintenance. What precautions to
be taken for Lead Acid Batteries?

### OR

(a) Mention advantages of MCB over Fuse.

##### MCB has several advantages over fuse:

MCB is more sensitive to current than the fuse. It detects any abnormality in the current flow and automatically switches off the electrical circuit.

In the case of MCB, the fault zone of the electrical circuit can be easily identified. Faulty circuit trips to the off position. On the other hand in case of the fuse, the complete fuse wire needs to be checked by opening fuse grip for confirming the fault zone.

With MCB it is very simple to resume to the supply. You just need to push the knob of MCB back to on position. But in case of the fuse, the entire fuse wire needs to be replaced.

MCB provides a better interface with the help of knob than a fuse. In case of the fuse, the compete for handle needs to be taken care out.

Handling MCB is electrically safer than handling a fuse.

MCB is reusable and hence has less maintenance and replacement cost. Whereas a fuse needs to be replaced whenever it goes faulty.

(b) Mention basic guidelines (Safety Rules) regarding safe handling of
electricity.

(c) Explain construction of cable in detail with neat diagram. Label all the
parts.

###### Read More : BME GTU Paper Solution Winter 2021

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