#mu engineering
- Explain the rusting of iron with the help of the electrochemical theory of corrosion and a diagram. Electrochemical (wet) theory: when a metal is in contact with moisture or an electrolyte, many tiny galvanic cells form on its surface. The... 1
- Define matrix and dispersed phase with its functions and examples. 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
- An alloy of Cd and Bi contains 25% Cd. Find the mass of eutectic in 1 kg of alloy if the system contains 40% Cd. Given: the alloy has 25% Cd (75% Bi). "The system contains 40% Cd" is taken to mean that the eutectic contains 40% Cd (60% Bi), as in the st... 1
- Explain the term ‘glass transition temperature’ with significance. Glass transition temperature (T_g) is the temperature below which an amorphous polymer (or the amorphous part of a polymer) is hard, rigid a... 1
- Define Matrix phase and dispersed phase with example. 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 are the principles of Green Chemistry. The 12 principles of Green Chemistry (Anastas and Warner): Prevention: it is better to prevent waste than to treat or clean it up after it i... 1
- 0.5 gm. of coal sample was burnt in Bomb calorimeter produced 0.06 gm. of BaSO4. calculate percentage of sulphur Given: mass of coal W = 0.5 g; mass of BaSO₄ = 0.06 g. Principle: S → SO₄²⁻ → BaSO₄. Since BaSO₄ = 233 and S = 32, 233 g of BaSO₄ contains 3... 1
- What is cathodic protection? How is it done by using impressed current and sacrificial anode? Explain with suitable examples. Cathodic protection: the metal to be protected is forced to act as the cathode of an electrochemical cell, so it does not corrode. Corrosion... 1
- Explain with neat suitable diagram determination of Carbon and hydrogen by ultimate analysis Principle: a known mass of coal is burnt completely in a current of dry, CO₂-free oxygen. Its carbon becomes CO₂ and its hydrogen becomes H₂... 1
- What do you mean by green solvent, explain it with suitable example. Green solvents are environmentally benign solvents that replace volatile, toxic and flammable organic solvents (benzene, CCl₄, CHCl₃). They... 1
- A Polymer has the following composition: 100 Molecules of molecular mass 1000, 200 molecules of molecular mass 2000 and 500 molecules of molecular mass 5000. Calculate the number and weight average of molecular weight and the polydispersity index. (P… Given: N_iM_iN_iM_iN_iM_i² 10010001.0 × 10⁵1.0 × 10⁸ 20020004.0 × 10⁵8.0 × 10⁸ 500500025.0 × 10⁵125.0 × 10⁸ Σ = 80030.0 × 10⁵134.0 × 10⁸ Num... 1
- What is condensed phase rule equation? Explain its application with the help of phase diagram to two component lead-silver system. Condensed (reduced) phase rule: Gibbs' phase rule is F = C − P + 2. In solid–liquid systems such as alloys the vapour phase is negligible, a... 1
- Explain Laminar and sandwich panel of structural composite. Structural composites are made of homogeneous and composite layers. Their properties depend on the constituent materials and on the geometri... 1
- Explain following properties of polymer a) Electrical b) Optical. a) Electrical properties – most polymers are good insulators because they have no free electrons or ions. Dielectric strength: the maximum e... 1
- Explain synthesis of Indigo dye by traditional way and by green pathway. Traditional (conventional) synthesis – Heumann–Pfleger process: undersetanilineC₆H₅NH₂ + HCHO + HCN → C₆H₅NHCH₂CN xrightarrowhydrolysis unde... 1
- A sample of coal has the following composition C = 80 %, O = 8%, H = 6 %, S = 1.5%, N = 1 %, Calculate the higher and lower calorific values of coal. Given: C = 80%, H = 6%, O = 8%, S = 1.5%, N = 1% (N does not contribute to the heat). Dulong's formula (C, H, O, S in %): HCV = 1/100[8080 C... 1
- Explain the effect of following factors on the rate of corrosion : (1) Nature of corrosion product. (2) pH (3) Anodic and cathodic areas (4) purity of metal (1) Nature of the corrosion product (oxide film): in dry corrosion the oxide layer formed on the surface decides further attack. Stable, non... 1
- Explain a) Fiber glass reinforced composite. b) Carbon fiber reinforced composite. a) Glass-fibre reinforced composite (GFRP / fibreglass) Constituents: continuous or chopped glass fibres (E-glass, S-glass), about 3–20 µm i... 1
- An alloy of tin and lead contain 73% tin. Find the mass of eutectic in 1kg of solid Alloy, if the eutectic contains 64% of tin. Given: the alloy has 73% Sn (27% Pb), and the eutectic has 64% Sn (36% Pb). The alloy has more Sn (73%) than the eutectic (64%). On cooling,... 1
- Explain mobility of electrons. The resistivity of Cu is 1.72 x 10-8 ohm-m. Calculate the mobility of electrons in Cu given that number of electrons per unit volume is 10.41 x 1028 m-3. Mobility (μ): When an electric field E is applied, free electrons acquire a drift velocity v_d proportional to E. Mobility is the drift velo... 1
- Derive an expression for Fermi level for an intrinsic semiconductor. In an intrinsic semiconductor, the electron concentration in the conduction band is n=N_c e^(-(E_c-E_F)/kT) and the hole concentration in th... 1
- Obtain the condition for maxima and minima of the light reflected from a thin transparent film of uniform thickness. Set-up: A thin transparent film of uniform thickness t and refractive index μ is in air. A ray AB is incident at angle i . Part of it is ref... 1
- An electron has a speed of 400 m/sec with uncertainty of 0.01%. Find the accuracy in its position. Given: v=400 m/s, so Δ v=0.01% of 400 =0.01/100×400=0.04 m/s. m=9.1×10⁻³¹ kg. Uncertainty principle: Δ x Δ p≥h/4π Δ x=h/4π mΔ v=frac6.63×10⁻... 1
- The refractive indices of core and cladding materials of a step index fibre are 1.48 and 1.45 respectively. Calculate (1) Numerical Aperture, (2) acceptance angle, (3) the critical angle at the core cladding interface, (4) fractional refractive indic… Given: n₁=1.48 , n₂=1.45 , n₀=1 (air). (1) Numerical aperture: NA=√(n₁²-n₂²)=√(2.1904-2.1025)=√(0.0879)=0.2965 (2) Acceptance angle: θ_a=sin... 1