First Year (FE)
- Write a short note on FET. Field Effect Transistor (FET): a three-terminal, unipolar (only majority carriers), voltage-controlled semiconductor device in which the cur... 1
- What is the efficiency of transformer? Efficiency of a transformer is the ratio of output power to input power: η = Output/Input = Output/Output + Losses = fracOutputOutput + P_i... 1
- Explain the working principle and transformation ratio of a single-phase transformer. Principle: mutual induction (Faraday's law). When an alternating voltage is applied to one winding, the alternating flux it produces links t... 1
- Draw and explain the V-I characteristics of a Zener diode Zener diode: a heavily doped silicon PN junction diode designed to operate in the reverse breakdown region without damage. Symbol: diode wit... 1
- Write formulas for Delta to Star and Star to Delta transformation. Let the delta resistances be R₁₂, R₂₃, R₃₁ (between terminals 1-2, 2-3, 3-1) and the equivalent star resistances be R₁, R₂, R₃ (connected fr... 1
- An alloy of Cd and Bi contain 25% of Cd Find the mass of eutectic in 1kg of solid Alloy, if the eutectic contains 40 % of Cd. Given: the alloy has 25% Cd (75% Bi), and the eutectic has 40% Cd (60% Bi). The alloy has less Cd (25%) than the eutectic (40%), so it has e... 1
- How material selection and proper design of equipments can prevent corrosion. Explain with the help of diagram and designing principles. 1. Proper selection of material Use noble or corrosion-resistant metals (Pt, Au, Ti) or alloys such as stainless steel and cupronickel where... 1
- A sample of coal has the following composition C = 84 %, O = 8.4 %, H = 5.5 %, S = 1.5%, N = 0.6 %, Calculate the higher and lower calorific values of coal. Given: C = 84%, H = 5.5%, O = 8.4%, S = 1.5%, N = 0.6% (N does not contribute to the heat). Dulong's formula (C, H, O, S in %): HCV = 1/100[... 1
- Explain fiber reinforced composite and write its applications and limitations. Fibre-reinforced composites (FRC) are composites in which the dispersed phase is in the form of fibres, i.e. long, thin filaments with a hig... 1
- Why are alloys preferred over pure metals in many applications? Pure metals are generally soft, ductile, of low strength, easily corroded and hard to cast. Alloying improves these properties, so alloys ar... 1
- What is condensed phase rule equation? Write merits and limitation of phase rule. Condensed (reduced) phase rule: the phase rule is F = C − P + 2. For solid–liquid equilibria such as alloys, the vapour phase is practically... 1
- Distinguish between galvanizing and tinning. GalvanizingTinning Iron or steel is coated with zinc, usually by dipping in molten Zn at about 450 °C.Iron or steel is coated with tin, usua... 1
- How do following factors affects the rate of corrosion i) PH medium ii) Purity of metal iii) Area of anode and cathode. i) pH of the medium: the rate of corrosion generally rises as pH falls, because acidic media supply H⁺ for the cathodic reaction (2H⁺ + 2e⁻... 1
- What are advantages of gaseous fuels over solid and liquid fuels? They can be carried easily through pipelines to the point of use, so there is no handling or storage labour. They mix intimately with air, s... 1
- 1 gm. of coal sample was used for determination of nitrogen. The ammonia evolved was passed into 50ml of 0.1 N H2SO4, the excess acid required 42 ml. of 0.1N NaOH for neutralization Calculate % of N. Given: W = 1 g; acid taken = 50 mL of 0.1 N H₂SO₄; excess acid = 42 mL of 0.1 N NaOH. Volume of 0.1 N acid used by NH₃ = 50 − 42 = 8 mL. %N... 1
- Explain the determination of sulphur present in coal sample and write its significance. Principle: the sulphur in coal is converted to sulphate and weighed as BaSO₄. Procedure A known mass (W g) of coal is burnt in a bomb calori... 1
- What is supercritical CO2 and how does it differ from liquid and gaseous CO2. Supercritical CO₂ (scCO₂) is CO₂ held above its critical temperature (T_c = 31.1 °C) and critical pressure (P_c = 72.8 atm ≈ 7.38 MPa). Abov... 1
- Write an informative note on biodiesel. Biodiesel is a mixture of mono-alkyl (methyl or ethyl) esters of long-chain fatty acids. It is made from vegetable oils (jatropha, karanja,... 1
- Explain synthesis of Adipic acid by traditional and green pathway. Also write the principle of green chemistry involved in this reaction. Conventional (traditional) route C₆H₆ xrightarrow[Ni / Pt]3H₂ undersetcyclohexanemathrmC₆H₁₂ xrightarrow[Co catalyst]O₂\ (air) undersetcyclo... 1
- Define Matrix phase and dispersed phase of composites. A composite has two constituents: 1. Matrix phase – the continuous phase that surrounds and binds the other phase. It may be a polymer, meta... 1
- Write a short note on sandwich panel of structural composite write its applications. Sandwich panel (a structural composite) A sandwich panel has two thin, strong and stiff outer face sheets (skins) bonded to a thick, lightwe... 1
- Explain viscoelasticity property of polymer. Viscoelasticity is the property of polymers by which they show both elastic (solid-like) and viscous (liquid-like) behaviour when deformed.... 1
- In a polymer sample 30% molecules have a molecular mass 20,000, 40% have molecular mass 30,000 and the 30% have 60,000. Calculate the weight average, number average molecular weight and polydispersity of polymer sample. Given (number fractions of molecules): take 100 molecules, so N_i = 30, 40, 30. N_iM_iN_iM_iN_iM_i² 3020,0006.0 × 10⁵1.2 × 10¹⁰ 4030,00012.0... 1
- Give the definitions and significance of following properties of polymer. Tensile strength, insulation resistance and refractive index. 1. Tensile strength Definition: the maximum tensile (pulling) stress a polymer specimen can withstand before it breaks: tensile strength = m... 1