Answer:
a) 
Explanation:
a) Let consider that heat pump is reversible, so that the Coefficient of Performance is:



The minimum heat received by the house must be equal to the heat lost to keep the average temperature constant. Hence:

The minimum power supplied to the heat pump is:



Answer:
(A)-Light-Bulb, Automobile Engine, Power Plant, Electric Motor
Explanation:
To get the least efficient to the most efficient the chart below explains how to the get it
Incandescent light bulb-5%
Florescent light bulb-20%
Electric motor-90%
Power plant-35%
Automobile engine-25%
Home oil furnace-80%
Answer:
critical stress required for the propagation is 27.396615 ×
N/m²
Explanation:
given data
specific surface energy = 0.90 J/m²
modulus of elasticity E = 393 GPa = 393 ×
N/m²
internal crack length = 0.6 mm
to find out
critical stress required for the propagation
solution
we will apply here critical stress formula for propagation of internal crack
( σc ) =
.....................1
here E is modulus of elasticity and γs is specific surface energy and a is half length of crack i.e 0.3 mm = 0.3 ×
m
so now put value in equation 1 we get
( σc ) =
( σc ) =
( σc ) = 27.396615 ×
N/m²
so critical stress required for the propagation is 27.396615 ×
N/m²
Answer:
D. Perform a thorough visual inspection.
Answer:
b)False
Explanation:
A battery is a device which store the energy in the form of chemical energy.And this stored energy is used according to the requirement.So battery is not a electromechanical device.Because it does have any mechanical component like gear ,shaft flywheel etc.
A flywheel is known as mechanical battery because it stored mechanical energy and supply that energy when more energy is required.Generally fly wheel is used during punching operation.