A diesel engine develops a Brake power of 4.5 kW. Its indicated thermal efficiency is 30% and the mechanical efficiency is 85%. Considering calorific value of the fuel as 40000 kJ/kg, the fuel consumption will be
ISRO Scientist or Engineer Refrigeration & Air-Conditioning 2019
For the following questions answer them individually
A cycle consisting of two reversible isothermal processes and two reversible isobaric processes is known as
A large clearance volume in a reciprocating compressor results in
Two beams have the same length, same allowable stresses and the same bending moment. The cross sections of the beams are a square and a rectangle with depth twice that of width.
The ratio of weight of square beam to the weight of rectangular beam is
Two shafts A and B are made of same material. The diameter of shaft B is twice that of shaft A. The ratio of power which can be transmitted by shaft A to that of shaft B is
The value of maximum deflection for a cantilever beam of length l and carrying uniformly varying load from zero at free end to w per unit length at fixed end is
In a riveted joint, when the number of rivets decrease from the innermost rowto outermost row, the joint is said to be
The process of reheating the martensitic steel to reduce its brittleness without any significant loss of hardnessis called
$$\frac{18}{8}$$ stainless steel contains
Crowning of pulley is done to
Flow of a liquid at a constant rate through a conical pipe is classified as
The comparison between pumps operating in series and in parallel is
A jet of water issuing from a nozzle strikes a flat plate normally (plane of plate makes an angle $$90^\circ$$ with the axis of the jet). The plate moves towards the nozzle with a velocity of 10 m/s while the jet issuing from the nozzle has a velocity of 15 m/s. The absolute velocity components of the jet (in m/s) as it leaves the vane, parallel (x component) and normal component (y component) to the undisturbed jet are. (Neglect friction on the surface).
The overall heat transfer coefficient (U) for a composite wall of thicknesses $$x_1, x_2, x_3$$ and of corresponding thermal conductivities $$k_1, k_2, k_3$$, is given by equation
Three metal walls of the same cross-sectional area having thermal conductivities in the ratio 1:2:4 transfers heat at the rate of 3000 kJ/hr. For the same wall thickness, the
temperature drops will be in the ratio
A electric heater of exposed surface area 0.09 m$$^2$$ and output 600 watts is designed to operate fully submersed in water. When the water is at $$37^\circ C$$ and the surface coefficient of heat transfer is 285.3 W/m$$^2$$-deg C, surface temperature of the heater will be
The highest value of thermal conductivity is expected for
The number of teeth of a spurgearis 30 and it rotates at 200 rpm. What will be its pitch line velocity if it has a module of ($$\frac{6}{\pi}$$) mm?
A force of 271 N is applied to the break drum of 2 m diameter in band brake system as shown in figure, where the wrapping angle is $$180^\circ$$. If the coefficient of friction between the drum and the band is 7/22, the braking torque applied in Nm is
Starting friction is low in which type of lubrication
A helical spring has N turns of coil diameter D and a second spring, made of same wire diameter and same material, has N/2 turns of coil of diameter 2D. If the stiffness of the first spring is k, then the stiffness of the second spring will be
A rigid rod PQ shown in Figure is connected to two sliders at each end through pins. The slider can slide along PR and QR. If the velocity of the slider at P is 4 m/s, the velocity of the midpoint of the rod PQ at this instant is
A concentrated mass m is attached at centre of a rod of length 2 L as shown in figure. The rod is kept in a horizontal equilibrium position by a spring of stiffness 4 k. For very small amplitude of vibration, neglecting the weight of the rod and spring, the undamped natural frequency ($$w_n$$) of the system is
At the time of starting, idling and low speed operation, the carburetor supplies a mixture which can be termed as
The crank radius of a single cylinder IC engine is $$\left(\frac{6}{\pi}\right)$$ mm and diameter of the cylinder is 40 mm. The swept volumeof the cylinder in cm$$^3$$ is
For the same values of peak pressure, peak temperature and heat rejection, the correct order of efficiencies for Otto, Duel and Diesel cycles
For determining the ignition quality of compression ignition engine fuels, the reference fuels used are
Air enters diesel engine with a density of 1 kg/m$$^3$$. The compression ratio is 21. At steady state, the air intake is $$21 \times 10^{-3}$$ kg/s and the network output is 20 kW. The Mean effective pressure (kPa) is
The purpose of providing supercharging for engine is
While designing refrigeration systemof anaircraft, the prime consideration is that
A good refrigerant should have
The bypass factorof cooling coil
The centrifugal compressorsare generally used for refrigerants that require
Equation of a line normal to $$f(x) = (x + 4)^{\frac{1}{2}} + 1$$ at Q(0, 3) is:
A box contains 2 blue, 3 black and 4 red balls. Balls are drawn from the box at random one at a time without replacement. The probability of drawing 2 blue balls first followed by 3 black balls and subsequently 4 red balls is
Using trapezoidal rule and dividing the interval of integration into three equal sub intervals, the definite integral $$\int_{-1}^{+1} \mid x \mid dx$$ is
A circularring of radius 42 cm is cut and bentinto the form of a rectangle whose sides are in the ratio of 6:5. The small side of the rectangle is
A tank is normally filled in 8 hours but takes 2 hours longer to fill because of a leak in the bottom. If the tank is full and due to leakage alone, the tank will get empty in
................. hours (Assume no further filling happens)
From a circular sheet of paper of radius 50 cm, a sector of 40% area is removed in the shape of an arc section. If the remaining part is used to make a conical surface, then the ratio of the radius to height of the cone is
Triple point of a substance
A liquid is boiling in a airtight vessel. Using an exhaust tube the vapour is pumped out at a faster rate. What will happento the liquid?
The equivalent evaporation rate (kg/hr) of a boiler producing 2000 kg/hr of steam with enthalpy content of 2426 kJ/kg from feed water at temperature 40 deg. C (liquid enthalpy = 168 kJ/kg and enthalpy of vaporization of water at 100 deg. C = 2258 kJ/kg) is
A cycle consisting of one constant pressure, one constant volume and two isentropic processes is known as
The maximum theoretical work obtainable, when a system interacts to equilibrium with a reference environment, is called
If a circular shaft is subjected to a torque T and a bending moment M, the ratio of the maximum shear stress to maximum bending stress is
A simply supported beamof length 3 mcarries a concentrated load of 12 kN at a distance of 1m from left support. The maximum bending momentin the beam is
A girder of uniform section and constant depth is freely supported over a span of 3 metres. The point load at the midpoint is 30 kN and Momentof inertia = $$15 \times 10^{-6} m^4$$ and youngs modulus = 200 GN/m$$^2$$. The deflection at centre will be
A copper rod 3 mm in diameter when subjected to a pull of 495 N extends by 0.07 mm over a gauge length of 100 mm. The youngs modulus for copper will be
When a body is subjected to three mutually perpendicular stresses of equal intensity, the ratio of direct stress to the expanding volumetric strain is known as
The bending moment in the centre of a simply supported beam carrying a uniformly distributed load of w per unit length is
A uniform wooden cylinder has a specific gravity of 0.5. Find the ratio of diameter to length of the cylinderso that it will just float upright in a state of neutral equilibrium in water
In s siphon, the summit is 3 m above the water level in the reservoir from which the flow is being discharged. If the head loss from the inlet of the siphon to the summit is 1.5 m and the velocity head at the summitis 0.5 m, the absolute pressure at the summit is
Two pipe lines of equal length and diameters of 10cm and 40cm are connected in parallel between two reservoirs. If friction factor f is same for both the pipes, the ratio of the
discharges in the larger to the smaller pipe is
The fluid property responsible for the problem of water hammer is
Within a boundary layer
The values of enthalpy of steamat inlet and outlet of a steam turbine in a Rankinecycle are 2800 kJ/kg and 1800 kJ/kg respectively. Neglecting pump work, the specific steam
consumptionin kg/kW-hour is
A pump handlinga liquid raises its pressure from 1 barto 30 bar. Take the density of liquid as 990 kg/m$$^3$$. The isentropic specific work done by the pumpin kj/kg is
A heat engine using lake water at $$12^\circ C$$ as source and the surrounding atmosphere at $$2^\circ C$$ as sink executes 1080 cycles per min. If the amount of heat drawn per cycle is 57 J, then the output of the engine will be
The unit of Stefan Boltzmann constant is
In a furnace, the wall thickness is 60 cm and is 100 cm wide by 150 cm height made of material with thermal conductivity 0.4 W/mK. The temperature inside and outside are $$1000^\circ C$$ and $$4^\circ C$$ respectively. The thermal resistance is
The rate of heat flow through a composite wall of three layers of thickness 0.3 m, 0.2 m, 0.15 m and of corresponding thermal conductivities 1.2, 0.8 and 0.6 kJ/hr-m$$^\circ C$$ is 1280 kd/hr. If the surface area normal to the direction of heat flow is 1 sq.mtr. and inner surface temperature is $$1000^\circ C$$, then the interface temperature at the end of first layer will be
For the four link mechanism with the dimensions of the links indicated in standard units of length, choose the type of mechanism from the given options
Operating pressure angle for involute gear teeth is
For the position of the mechanism shown in Figure, find the velocity of the slider B for the given configuration if the velocity of the slider A is 3 m/s. Consider AB as a rigid link and is parallel to CD at this instant.
The device used to heat feed water by utilizing the heat of the exhaust flue gases before leaving through the chimney is called
The power consumed by a reciprocating air compressor will be minimum, if the compression follows the following thermodynamic process
In an impulsereaction turbine stage, the heat drop in fixed and moving blades are 20 kJ/kg and 30 kJ/kg respectively. The degree of reaction for this stage will be
Which among the following automobile exhaust gas pollutants is a major cause of photochemical smog?
In a two stage reciprocating air compressor with a suction pressure of 4 bar and delivery pressure of 16 bar, the ideal intercooler pressure will be
In PERT chart, the activity time distribution is
Dew point temperature lines on the psychometric chart are
The lowest temperature during the cycle in a vapour compression system occurs after
The principle of vapour compression system is that fluids absorb heat while changing from a
Sensible heat factor is defined as the ratio of
In vapour compression refrigeration system, heatrejected as compared to heat absorbed is
As warm air cools, it’s relative humidity
Consider the shaded triangle region P shown in the figure
What is $$\int\int_{P} xydxdy$$
Distance between origin and_ the point nearest to it on the surface $$z^2 = 1 + xy$$ is:
At $$x = 0$$, the function $$f(x) = \mid x \mid$$ has
General solution of differential equation $$\frac{dy}{dx} = \cos(x + y)$$ is
