GATE 2021 ME : Toppers Quiz 32 (App update required to attempt this test)

What should be the value of Joule- Thompson coefficient for decrease in temperature during throttling process

Which of the following is true for Inventory control?

What is the minimum frequency used in ultrasonic welding?

A helicopter propeller rotates in counter-clockwise direction when seen from the top about the vertical axis. The helicopter takes a left turn in the horizontal plane about the vertical axis. The effect of gyroscopic couple will be

Temperature and velocity profiles are identical when the dimensionless Prandtl number is

A uniformly tapering circular bar is subjected to an axial force P. The bar has length L, diameter at one end is d₁ and on the other end is d₂ (d₂ >d₁). The Young’s Modulus of material of bar is E. The change in length of the bar is

In a orthogonal turning operation the chip thickness, ratio is 0.5 and the rake angle,  is 10.What is the coefficient of friction for minimum power consumption?

Water at 90 flowing at the rate of 2 kg/s mixes adiabatically with another stream of water at 30 flowing at the rate of 1 kg/s . For an ambient temperature of 300 K, the exergy loss due to mixing is _____ kW

A plane slab of thickness L and thermal conductivity k is heated with a fluid on one side and the other side is maintained at a constant temperature, T_Q of 25^°C, as shown in the figure. The fluid is at 45^°C and the surface heat transfer coefficient, h, is The steady state temperature. T_P (in ^°C) of the side which is exposed to the fluid is _________ (correct to two decimal places).

A 1 cm diameter, 30cm long fin made of aluminum (k = 237 W/m-^oC) is attached to a surface at 80^oC. The surface is exposed to ambient air at 22^oC with a heat transfer coefficient of 11 W/m²-^oC. If the fin can be assumed to be very long, its efficiency is

A vapour compression refrigerator system operating at an evaporator temperature of –5 °C and condenser temperature of 40 °C with mass flow rate of refrigerant is 21.0 kg/min. The refrigerant, R-12 is subcooled 5 °C before entering the expansion valve and vapour is superheated 6 ° C in evaporator coil. If the clearance is 2% then the piston displacement volume (in m³/min) is
Properties of R-12

(liquid)=0.963kJ/kgK
(vapour)=0.7035kJ/kgK

An air standard Otto cycle has thermal efficiency of 0.5 and the mean effective pressure of the cycle is 1000 kPa. For air, assume specific heat ratio γ = 1.4 and specific gas constant R = 0.287 kJ/kg.K, If the pressure and temperature at the beginning of the compression stroke are 100 kPa and 300 K, respectively, then the specific net work output of the cycle is ___________kJ/kg (round off to two decimal places).

A steady laminar boundary layer is formed over a flat plate as shown in the figure. The free stream velocity of the fluid is U_o. The velocity profile at the inlet a-b is uniform, while that at a downstream location c-d is given by u = U_o.

The ratio of the mass flow rate, 𝑚𝑏, leaving through the horizontal section b-d to that entering through the vertical section a-b is ___________

On cooling, a solid phase and liquid phase together form in solid phase during __________ reaction.

An epicyclic gear train is shown schematically in the adjacent figure

The sun gear 2 on the input shaft is a 20 teeth external gear. The planet gear 3 is a 40 teeth external gear. The ring gear 5 is a 100 teeth internal gear. The ring gear 5 is fixed and the gear 2 is rotating at 80 r.p.m ccw (ccw=counter-clockwise and cw =clockwise).
Then arm attached to the output shaft will rotate at ____.

Two very large parallel plates have emissivities  = 0.5 and  = 0.9. the plates are maintained at uniform temperatures of  = 600K and  = 400K. What will be the net rate of radiation heat transfer between the two surfaces per unit area of the plates?