List of top Questions asked in GATE XE

The parboiling of paddy results into:

One hundred kg paddy is dried from 18% wet basis to 13% wet basis moisture content. The amount of water removed (in kg) from the paddy is _________ (round off to one decimal place).

Match the following polymers to the most appropriate product

Match the polymers to the polymerization method used for their synthesis:

If 5 g of a monodisperse polystyrene sample of molecular weight 10,000 g mol$^{-1}$ is mixed with 15 g of another monodisperse polystyrene sample of molecular weight 20,000 g mol$^{-1}$, then the polydispersity of the resulting mixture is _________ (rounded off to two decimal places).

For a polymer sample with a viscosity of $6 \times 10^{11}$ poise, if the apparent plateau modulus of $3 \times 10^6$ dyne cm$^{-2}$ drops to zero above a certain temperature, the relaxation time of the polymer is _________ days (rounded off to one decimal place).

The tensile modulus of a thermosetting polyester resin and glass fiber are 3 GPa and 80 GPa, respectively. If a tensile stress of 110 MPa is applied along the fiber direction on a continuous uniaxially aligned glass fiber reinforced thermosetting polyester composite with a fiber content of 60% by volume, the resulting strain will be _________ \times 10^{-3} \text{ (round off to one decimal place).}

The amount of low molecular weight plasticizer with a $T_g$ of -60°C that must be added to nylon 6 to reduce its $T_g$ from 50°C to 30°C is _________ % (rounded off to nearest integer).

The enthalpy of fusion for a polymer is found to decrease from 135.6 J g$^{-1}$ to 120 J g$^{-1}$ after five years of use. If the enthalpy of fusion of the same polymer with 100% crystallinity is 290 J g$^{-1}$, then the loss in crystallinity after five years is _________ % (rounded off to one decimal place).

Which of the following polymers are polyesters?

The functionality of adipic acid for condensation reaction with glycerol is _________ (in integer).

From the dynamic mechanical analysis of a polymer sample with a phase angle of 30°, the relationship between storage modulus \( E' \) and loss modulus \( E'' \) can be expressed as:

Match the properties in Column A with their respective unit in Column B:

Match the following polymer product with its most appropriate processing technique

Match the following additives to their respective functions:

Match the polymers with their characteristic infrared (IR) stretching frequency.

In a rubber sample with a Mooney viscosity of 60 ML(1+4) 100°C, the number 4 signifies

The initiator system which can be used for free radical polymerization at 5°C is:

Weather resistance of high impact polystyrene can be improved by blending polystyrene with:

Which of the following is a discontinuous polymer processing operation?

The blend of polyethylene and polypropylene is:

Toughness in a polymer can be inferred from

An insulated rigid tank of volume 10 m$^3$ contains air initially at 1 MPa and 600 K. A valve connected to the tank is opened, and air is allowed to escape until the temperature inside the tank drops to 400 K. The temperature of the discharged air can be approximated as the average of the initial and final temperatures of the air in the tank. Neglect kinetic and potential energies of the discharged air. Assume that air behaves as an ideal gas with constant specific heat so that internal energy $u = c_p T$ and enthalpy $h = c_p T$. Then, the final pressure of the air in the tank is _________ MPa (round off to 2 decimal places). Assume: $c_p = 1.005$ kJ/(kg K), $\gamma = \frac{c_p}{c_v} = 1.4$

Steam enters a steam turbine at 5 MPa and 600°C, and exits as saturated vapor at 50 kPa. Under steady state condition, the turbine loses heat to the surroundings at the rate of 50 kJ per kilogram of steam flowing through the turbine. The ambient temperature is 300 K, and the heat transfer to the surroundings takes place at the outer surface of the turbine at a temperature of 450 K. The irreversibility per unit mass of steam flowing through the turbine is _________ kJ/kg (round off to 2 decimal places).

A heat engine receives heat at 1000 K and rejects heat to environment at 300 K. Its efficiency is half that of a Carnot engine operating between these temperatures. The work output drives a refrigerator removing heat from a cold space at 260 K at 5.2 kW, rejecting heat at 300 K. The refrigerator COP is half of the Carnot refrigerator. Find the rate of heat supplied to the heat engine (kW). Round off to 2 decimals.