Indian Institute of Technology Madras (IIT-M) 2003 M.Tech Mechanical Engineering mechanical engg-gate - Question Paper

(a) diameter in millimeter x length in meter
(b) diameter in centimeter x length in meter
(c) number of strands x number of wires in every strand
(d) number of wires in every strand x number of strands
13. A cylindrical body of cross-sectional area A, height H and density p, is immersed to a
depth h in a liquid of density p. and tied to the bottom with a string. The tension in the string
is
(a) pghA
(b) (p5—p)ghA
(c) (p—p5)ghA
(d) (ph—p5H)gA
14. A two kW, 40 litre water heater is switched on for 20 minutes. The heat capacity C for water
is 4.2 kJ/kg K. Assuming all the electrical energy has gone into heating the water, increase of
the water temperature in degree centigrade is
(a) 2.7
(b) 4.0
(c) 14.3
(d) 25.25
15. An industrial heat pump operates ranging from the temperatures of 27°C and —13°C. The
rates of heat addition and heat rejection are 750 W and 1000W, respectively. The COP for the
heat pump is
(a) 7.5
(b) 6.5
(c) 4.0
(d) 3.0
16. A plate having 10 cm2 area every side is hanging in the middle of a room of 100
m2 total surface area. The plate temperature and emissivity are respectively 800
K and 0.6. the temperature and emissivity values for the surfaces of the room
are 300K and 0.3 respectively. Boltzmann’s constant G=5.67x108 W/m2K4. The
total heat loss from the 2 surfaces of the plate is
(a) 13.66 W
(b) 27.32 W
(c) 27.87 W
(d) 13.66 W
17. For air with a relative humidity of 80%
(a) the dry bulb temperature is less than the wet bulb temperature
(b) the dew point temperature is less than wet bulb temperature
(c) the dew point and wet bulb temperatures are equal

(d) the dry bulb and dew point temperatures are equal
18. For a spark ignition engine, the equivalence ratio (0) of mixture entering the
combustion chamber has values.
(a) 0 < one for idling and 0 > one for peak power conditions.
(b) 0 > one for both idling and peak power conditions.
(c) 0 > one for idling and 0 < one for peak power conditions.
(d) 0 < one for both idling and peak power conditions.

Earning:   Approval pending.