List of top Questions asked in GATE Engineering Sciences

In the figures given below, L and H indicate low and high pressure centers, respectively; PGF, CoF and CeF indicate Pressure Gradient Force, Coriolis Force and Centrifugal Force, respectively; \( V \) is Velocity. [The arrows indicate only the directions but not the magnitudes of the forces and velocity.]

Which of the following is/are the correct representation(s) of the directions of various forces and velocity in the gradient wind balance in the northern hemisphere?
 

Which of the following is the correct form of the mass divergence form of the continuity equation for a compressible fluid? [In the given equations, \( \rho \) is the density and \( \nabla \) the three-dimensional velocity vector of the fluid.] 
[(i)] $\displaystyle \frac{\partial \rho}{\partial t} + \nabla \times (\rho \mathbf{v}) = 0$
[(ii)] $\displaystyle \frac{\partial \rho}{\partial t} + \nabla \cdot (\rho \mathbf{v}) = 0$ 
[(iii)] $\displaystyle \frac{\partial \mathbf{v}}{\partial t} + \rho \cdot \nabla \mathbf{v} = 0$ 
[(iv)] $\displaystyle \frac{\partial \rho}{\partial t} + \mathbf{v} \cdot \nabla \rho = 0$

The vertical (depth) profiles for three parameters P1, P2, and P3 in the northern Indian Ocean are given in the figure below. The values along the x-axis are the normalized values of the parameters and y-axis is the depth (m). 

Identify the parameters P1, P2, and P3 from the options given below.
 

The sea surface height concentric isolines (L1 and L2 in cm) and the distance between them (dx in km) for three different eddies at the same latitude are given in the figure below. (The figures are not to scale.) 

Which one of the following orders is correct about the magnitudes of the geostrophic currents within the isolines? 
 

Potato slices weighing 50 kg is dried from 60% moisture content (wet basis) to 5% moisture content (dry basis). The amount of dried potato slices obtained (in kg) is ............ (Answer in integer)

The crystallization of a polymer can only proceed in a temperature range limited to glass transition temperature (\(T_g\)) on the lower side, and the equilibrium melting point (\(T_m^0\)) on the higher side. Around \(T_g\), the mobility of the polymer chains is lower, while in the proximity of \(T_m^0\), crystal nucleation is inhibited.
In a miscible polymer blend with only one component being crystalline, which option(s) correctly match(es) the Temperature conditions with Events? 

In a set of copolymerization reactions, the following monomer reactivity ratios (\(r_1\) and \(r_2\)) were found for different cases. 

Which option(s) correctly identify/identifies the type of copolymerization corresponding to each Case?

Which option(s) correctly match(es) the Class of additives used during polymer compounding with the corresponding Chemicals? 

Which option(s) correctly match(es) the Polymer property with its appropriate Units? 

During material testing, stress is applied from time \(t_i\) to \(t_f\) as shown below: 

Choose the option(s) where the strain response is correctly mapped to its material class.

Choose the option(s) that correctly match(es) the Zones with their typical Functions in an industrial extruder. 

The ‘unperturbed dimension’ of the polymer chain is represented as, \[ \left( \overline{r^2_0} \right)^{1/2} \propto \overline{\ell}(n)^{1/2} \] where, \(\left( \overline{r^2_0} \right)^{1/2}\) = root-mean square end-to-end distance
\(\overline{\ell}\) = average length of a segment
\(n\) = number of segments in the chain
Using the above information, root-mean square end-to-end distance of a branched polyethylene would be ............. when compared with that of the linear polyethylene of the same molecular weight and the same number of segments.

Injection molding is typically used to make plastic parts. If the pressure at the gate is monitored as a function of time during the injection of a thermoplastic polymer, identify the profile that best describes this event. 

Match the Polymer with the most suitable Monomer combinations from which it is synthesized.

Match the Product with the most appropriate Processing Technique employed.

In a polymer recycling plant, polymer “X” was depolymerized by glycolysis in the presence of ethylene glycol and a suitable catalyst. The glycolysis reaction yielded the following compound: 

Identify the polymer “X” from the following options.

A stream of superheated steam (2 MPa, 300°C) mixes with another stream of superheated steam (2 MPa, 400°C) through a steady-state adiabatic process. The flow rates of the streams are 3 kg/min and 2 kg/min, respectively. This mixture then expands in an adiabatic nozzle to a saturated mixture with quality of 0.77 and 1 kPa. Neglect the velocity at the nozzle entrance and the change in potential energies. The velocity at the nozzle exit (in m/s) is ......... (rounded off to two decimal places). 
Use the following data:
At 2 MPa, 300 °C: Specific enthalpy of superheated steam = 3024.2 kJ/kg
At 2 MPa, 400 °C: Specific enthalpy of superheated steam = 3248.4 kJ/kg
At 1 kPa: Specific enthalpy of saturated water = 29.3 kJ/kg
At 1 kPa: Specific enthalpy of saturated vapour = 2513.7 kJ/kg