A spherical waterdrop of 1 mm in diameter splits up in air into 64 smaller drops of equal size. The surface tension coefficient of water in air is 0.073 N/m. The work required in splitting up the drop is

Consider the following statements pertaining to stability of floating bodies:
1. A floating body will be stable when the centre of gravity is above the centre of buoyancy.
2. The position of metacentres corresponding to different axes of rotation are generally different for the same floating object.
3. For cargo ships, the metacentric height varies with loading.
Which of the above statements are correct?

Water is coming out from a tap and falls vertically downwards. At the tap opening, the stream diameter is 20 mm with uniform velocity of 2 m/s. Assuming steady inviscid flow, constant pressure atmosphere everywhere, and neglecting curvature and surface tension effects, the diameter of the stream 0.5 m below the tap opening is nearly

Consider the following statements:
1. At low Reynolds numbers of any flow, viscous forces dominate over inertial forces.
2. Transition from laminar to turbulent flow occurs over a range of Reynolds numbers depending on the surface presented to the flow.
Which of the above statements is/are correct?

In a steady laminar flow of a given discharge through a circular pipe of diameter D, the head loss is proportional to

The centre-line velocity in a pipe flow is 2m/s. What is the average flow velocity in the pipe if the Reynolds number of the flow is 800?

During a constant pressure expansion of a gas, 33.3% heat is converted into work while the temperature rises by 20 K. The specific heat of the gas at constant pressure as a proportion of work, W is

A system of 100 kg mass undergoes a process in which its specific entropy increases from 0.3 kJ/kg K to 0.4 kJ/kg K. At the same time, the entropy of the surroundings decreases from 80 kJ/kg K to 75 kJ/kg K. The process is

A reversible heat engine rejects 80% of the heat supplied during a cycle of operation. If the engine is reversed and operates as a refrigerator, then its coefficient of performance shall be

For the same efficiency of the Brayton cycle and the Carnot cycle working between temperature limits of T_max and T_min, the power contribution of the Brayton cycle will be

A heat engine working on the Carnot cycle receives heat at the rate of 50 kW from a source at 1300 K and rejects it to a sink at 400 K. The heat rejected is

An ideal gas is flowing through an insulated pipe at the rate of 3.3 kg. There is a pressure drop of 15% from the inlet to the outlet of the pipe. What is the rate of energy loss because of this pressure drop due to friction, given that R_gas= 0.287 kJ/kg K and the reference temperature T0 is 300 K?

A furnace is provided with an insulating refractory lining. The overall thermal conductivity of the material is 0.03 W/mK. The thickness of the lining is 100 mm. The inner and outer temperatures are 250°C and 50°C, respectively. The heat loss to the surroundings will be

A wall of 0.6m thickness has normal area of 1.5 m² and is made up of material of thermal conductivity 0.4 W/mK. If the temperature on the two sides of the wall are 800°C and 1000°C, the thermal resistance of the wall is

Heat is lost from a 100 mm diameter steam pipe placed horizontally in ambient air at 30°C. If the Nusselt number is 25 and the thermal conductivity of the air is 0.03 W/m K, then the heat transfer coefficient will be

Knocking in a spark ignition engine can be reduced by
1. retarding the spark
2. supercharging
3. increasing the engine speed
4. using a fuel of long straight chain structure Select the correct answer using the code given below.

A 4-cylinder diesel running at 1200 r.p.m. developed 18.6 kW. The average torque when one cylinder was cut out was 105 N m. If the calorific value of the fuel was 42000 kJ/kg and the engine used 0.34 kg of diesel/kW hr, the indicated thermal efficiency was nearly

In a Morse test on a 2-cylinder, 2-stroke SI engine, the brake power is 9 kW and the BHP of individual cylinders with spark cutoff are 4.25 kW and 3.75 kW, respectively. The mechanical efficiency of the engine is

Consider the following statements for refrigeration and air-conditioning:
1. In a refrigerating machine, the heat exchanger that absorbs heat is connected to a conditioned space.
2. A refrigerating cycle operating reversibly between two heat reservoirs has the highest coefficient of performance.
3. The lower the refrigeration required and the higher the temperature of heat rejection to the surroundings, the larger the power consumption.
Which of the above statements are correct?

In a refrigerator, the evaporator and condenser coil temperatures are –33°C and 27°C, respectively. Assuming that the maximum COP is realized, the required power input for a refrigerating effect of 4 kW is

Consider the following statements: The volumetric efficiency of a reciprocating compressor can be improved by
1. decreasing the clearance volume
2. cooling the intake air
3. heating the intake air
Which of the above statements is/are correct?

Consider the following statements :
The presence of air inside condensers
1. remains as a non-condensable gas
2. reduces the condensing coefficient
3. tends to cling to the surface
4. introduces large thermal resistance
Which of the above statements are correct?

The refrigeration system of an ice plant working between temperatures of –5°C and 25°C produces 20 kg of ice per minute from water at 20°C. The specific heat of water is 4.2 kJ/kg and latent heat of ice is 335 kJ/kg. The refrigeration capacity of the refrigeration plant is

Consider the following statements in respect of a vapour-absorption refrigeration cycle :
1. The absorption refrigeration cycle is generally used when waste heat is available from an existing source or when free energy like solar energy is to be used.
2. There are no moving parts in the absorption refrigeration plant except a small liquid pump.
3. The value of the coefficient of performance is nearly the same in both vapour-absorption and vapour- compression refrigeration plants.
Which of the above statements are correct?

Air at 30°C and 1 bar has a specific humidity of 0.016 kg/kg of dry air. By considering the saturation pressure of water vapour at 30°C as 4.246 kPa, the relative humidity of the air will be

Consider the following statements in respect of an evaporative cooling process :
1. The wet-bulb temperature remains constant.
2. The dew-point temperature remains constant.
3. The enthalpy remains constant.
Which of the above statements are correct?

Which of the following statements are correct?
1. The specific speed of a turbine is the speed at which a homologous turbine develops 1 mhp under unit heat at its maximum efficiency.
2. The specific speed is a dimensionless parameter used for the selection of turbines.
3.The function of guide vanes in reaction turbines is to minimize shock at entry of the fluid onto the runner blades.
Select the correct answer using the code given below :

A centrifugal pump lifts 0.0125m³/sof water from a well with a static lift of 30 m. If the brake power of the driving electric motor is 5 kW, what is the overall efficiency of the pump-set?

Consider the following statements in respect of ideal and practical gas turbine cycles:
1. In the ideal cycle case, the cycle efficiency depends on the pressure ratio only.
2. In the practical cycle case (with irreversibilities in the compression and expansion processes), The cycle efficiency depends on the maximum temperature as well as on the pressure ratio.
3. In the practical cycle case, at a given maximum temperature, the maximum efficiency and the maximum work done occur at a same pressure ratio.
Which of the above statements are correct?

A jet of water issues from a sharp-edged vertical orifice under a constant heat of 0.51 m. At a certain point of the issuing jet, the horizontal and vertical coordinates measured from vena contracta are 0.406 m and 0.085 m, respectively. What is the value of the coefficient of velocity?