# A cyclic device operates between three thermal reservoirs, as shown in the figure. Heat is transferred  to/form the cyclic device. It is assumed that heat transfer between each thermal reservoir and the cyclic device takes place across negligible temperature difference. Interactions between the cyclic device and the respective thermal reservoirs that are shown in the figure are all in the form of heat transfer

1.  a reversible hear engine

2.  a reversible heat pump or a reversible refrigerator

3.  an irreversible heat engine

4.  an irreversible heat pump or an irreversible refrigerator

4

a reversible hear engine

Explanation :
No Explanation available for this question

# A balloon containing an ideal gas is initially kept in an evacuated and insulated room- The balloon ruptures and the gas fills up the entire room. Which one of the following statements is TRUE at the end of above process

1.  The internal energy of the gas decreases from its initial value, but the enthalpy remains constant

2.  The internal energy of the gas increases from its initial value, but the enthalpy remains constant

3.  Both internal energy and enthalpy of the gas remain constant

4.  Both internal energy and enthalpy of the gas increase

4

Both internal energy and enthalpy of the gas remain constant

Explanation :
No Explanation available for this question

# For the three-dimensional object shown in the figure below, five faces are insulated. The sixth face (PQRS), which is not insulated, interacts thermally with the ambient, with a convective heat transfer coefficient of 10 W/m2K. The ambient temperature is 30°C. Heat is uniformly generated inside the object at the rate of 100 W/m3. Assuming the face PQRS to be at uniform temperature, its steady state temperature is

1.  10°C

2.  20°C

3.  30°C

4.  400C

4

20°C

Explanation :
No Explanation available for this question

# Water, having a density of 1000 kg/m3, issues from a nozzle with a velocity of 10 m/s and the jet strikes a bucket mounted on a Pelton wheel. The wheel rotates at 10 rad/s. The mean diameter of the wheel is 1 m. The jet is split into two equal streams by the bucket, such that each stream is deflected by 120°, as shown in the figure. Friction in the bucket may be neglected. Magnitude of the torque exerted by the water on the wheel, per unit mass flow rate of the incoming jet, is

1.  0(N. m)/(kg/s)

2.  1.25 (N. m)/(kg/s)

3.  2.5 (N. m)/(kg/s)

4.   3.75 (N. m)/(kg/s)

4

3.75 (N. m)/(kg/s)

Explanation :
No Explanation available for this question

# A thermal power plant operates on a regenerative cycle with a single open feedwater heater, as shown in the figure. For the state points shown, the specific enthalpies are: h, = 2800 kj/kg and h2 = 200 kj/kg. The bleed to the feed water heater is 20% of the boiler steam generation rate. The specific enthalpy at state 3 is

1.  720 kJ/kg

2.  2280 kJ/kg

3.  1500 kJ/kg

4.  3000 kJ/kg

4

720 kJ/kg

Explanation :
No Explanation available for this question

# Moist air at a pressure of 100 kPa is compressed to 500 kPa and then cooled to 35°C in an after cooler. The air at the entry to the after cooler is unsaturated and becomes just saturated at the exit of the after cooler. The saturation pressure of water at 35°C is 5.628 kPa. The partial pressure of water vapour (in kPa) in the moist air entering the compressor is closest to

1.  0.57

2.  1.13

3.  2.26

4.  4.52

4

1.13

Explanation :
No Explanation available for this question

# A hollow enclosure is formed between two infinitely long concentric cylinders of radii 1 m and 2 m, respectively. Radiative heat exchange takes place between the inner surface of the larger cylinder (surface-2) and the outer surface of the smaller cylinder (surface-1). The radiating surfaces are diffuse and the medium in the enclosure is non-participating. The fraction of the thermal radiation leaving the larger surface and striking itself is

1.  0.25

2.  0.5

3.  0.75

4.  1

4

0.5

Explanation :
No Explanation available for this question

# Steady two-dimensional heat conduction takes place in the body shown in the figure below. The normal temperature gradients over surfaces P and Q can be considered to be uniform. The temperature gradient ∂T/∂x at surface Q is equal to 10 K/m. Surfaces P and Q arc maintained at constant temperatures as shown in the figure, while the remaining part of the boundary is insulated. The body has a constant thermal conductivity of 0.1 W/m. K. The values of ∂T/∂x and ∂T/∂y  at surface P are

1.  ∂T/∂x=20 K/m, ∂T/∂y=0 K/m

2.  ∂T/∂x=0 K/m, ∂T/∂y=10 K/m

3.  ∂T/∂x=10 K/m, ∂T/∂y=10 K/m

4.  ∂T/∂x=0 K/m, ∂T/∂y=20 K/m

4

∂T/∂x=0 K/m, ∂T/∂y=20 K/m

Explanation :
No Explanation available for this question

# In a steady state steady flow process taking place in a device with a single inlet and a single outlet, the outlet work done per unit mass flow rate is given by  where v is the specific volume and p is the pressure. The expression for w given above

1.  is valid only if the process is both reversible and adiabatic

2.  is valid only if the process is both reversible and isothermal

3.  is valid for any reversible process

4.  is incorrect; it must be

4

is valid for any reversible process

Explanation :
No Explanation available for this question

1.  mn

2.  2(m + n)

3.  m + n

4.  m + n – 1

4