# Mechanical Engineering - Heat Transfer, Refrigeration and Air Conditioning

Exercise : Heat Transfer, Refrigeration and Air Conditioning - Section 7
21.
The emissive power of a body depends upon its
temperature
physical nature
wave length
all of these
Explanation:
No answer description is available. Let's discuss.

22.
An electric cable of aluminium conductor (k = 240 W/mK) is to be insulated with rubber (k = 0.15 W/mK). The cable is to be located in air (h = 6 W/m2). The critical thickness of insulation will be
25 mm
40 mm
160 mm
800 mm
Explanation:
No answer description is available. Let's discuss.

23.
A cube at high temperature is immersed in a constant temperature bath. It loses heat from its top, bottom and side surfaces with heat transfer coefficients of h1, h2 and h3 respectively. The average heat transfer coefficient for the cube is
h1 + h2 + h3
(h1h2h3)1/3
none of these
Explanation:
No answer description is available. Let's discuss.

24.
The dehumidification process, on the psychrometric chart, is shown by
horizontal Sine
vertical line
inclined line
curved line