First Year (FE)
- 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
- 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
- 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
- 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
- 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
- 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
- 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 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
- 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
- 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
- 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
- Give the purposes of making of an alloy. Alloys are made in order to: Increase hardness and strength. Pure metals are soft. Example: adding C to Fe gives steel; adding Cu to Au make... 1
- Define corrosion, how you will join the metals to prevent corrosion, justify with diagram. Corrosion is the gradual destruction or deterioration of a metal by chemical or electrochemical attack from its environment, starting at the... 1
- What are the characteristics of good fuel? A good fuel should: Have a high calorific value, so it gives more heat per unit mass. Have a moderate ignition temperature. If it is too low... 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
- State Ampere’s Circuital law. Derive Maxwell’s fourth equation in differential form. Ampere's circuital law: The line integral of the magnetic field intensity vec H around any closed path equals the net current enclosed by th... 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
- 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
- With a neat energy level diagram, describe the construction and working of He-Ne Laser. He–Ne laser is a four-level gas laser that gives a continuous output at 6328 Å (red). Construction: discharge tube (He:Ne ≈ 10:1, ~1 mm Hg)... 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
- Calculate the wavelength of de-Broglie waves associated with mass 1 kg moving with a speed of 103 m/sec. Given: m=1 kg, v=10³ m/s, h=6.63×10⁻³⁴ J s. Formula: λ=h/mv λ=frac6.63×10⁻³⁴1×10³=6.63×10⁻³⁷\ m λ=6.63×10⁻³⁷ m This is far too small to dete... 1
- Write Fermi- Dirac distribution function and explain the terms in it. The Fermi–Dirac distribution function gives the probability that an available energy state E is occupied by an electron at absolute temperat... 1
- Show that the divergence of the curl of a vector is zero. Let vec A=A_xhat i+A_yhat j+A_zhat k . nabla×vec A=Big(∂ A_z/∂ y-∂ A_y/∂ zBig)hat i+Big(∂ A_x/∂ z-∂ A_z/∂ xBig)hat j+Big(∂ A_y/∂ x-∂ A_x/∂ y... 1