C:-forced convection and conduction
D:-free and forced convection
Correct Answer:- Option-C
Question47:-LMTD in case of counter flow heat exchanger as compared to parallel flow heat exchanger is
A:-higher
B:-lower
C:-same
D:-depends on the area of heat exchanger
Correct Answer:- Option-A
Question48:-Which mechanism of heat transfer is involved in heating a pot with water on a stove ?
A:-Convection
B:-Conduction
:-Radiation
D:-Induction
Correct Answer:-Question Cancelled

Question49:-The heat transfer by radiation from a mild steel surface is to be reduced by reducing the emissivity of the
surface. This can be best achieved by

A:-painting the surface black
B:-roughening the surface
C:-surface a mirror finish
D:-none of these
Correct Answer:- Option-C
Question50:-Water enters a thin walled tube (L=1m, D=3mm) at an inlet temperature of 97°C and mass flow rate 0.015 kg/s.
The tube wall is maintained at a constant temperature of 27°C. Given the following data for water
Density ‘rho’ = 1000 kg/*m*(3)*, Viscosity ‘mu* = 489x*10%(-6) Ns/*m*(2)°, Specific heat *C_(p)’ = 4184J/kg/K
Inside heat transfer coefficient h = 12978 W/('m*(2) K)
The outlet temperature of water in °C is
A:-28
B:-37
C:-62
D:-96
Correct Answer:- Option-B
Question51:-Prandtl number is the ratio of
A:-mass diffusivity to thermal diffusivity
B:-Momentum diffusivity to thermal diffusivity
C:-Thermal diffusivity to mass diffusivity
D:-thermal diffusivity to momentum diffusivity
Correct Answer:- Option-B
Question52:-Which one of the following statements is true with regards to the percentage saturation (P.S) and relative
saturation (R.S) ?
A:P.S = RS
52௩5
S< RS
D:-P.S and R.S are not inter related
Correct Answer:- Option-C

Question53:-The feed to a binary distillation column has 40 mole% vapour and 60 mole% liquid. Then the slope of the q-line
in the McCabe-Thiele plot is

5
:--0.6
C:-0.6
D:-1.5
Correct Answer:- Option-A
Question54:-1000 kg of wet solids are to be dried from 60% to 20% moisture (by weight). The mass of moisture removed in
kg is
A:-100 kg
B:-200 kg
0:-500 kg
D:-400 kg
Correct Answer:- Option-C
Question55:-'* When a multistage try tower uses a minimum reflux ratio it implies ?