Answer:
On a surface.
Explanation:
Asperities are microscopic peaks and valleys on a surface. This simply means that, when asperities contacts, surfaces also make contact. Asperities are the roughness or unevenness of a surface coming in contact during wear or friction.
Answer:
Maximum allowable chip power is 0.35 W
Explanation:
This question is incomplete. The complete question is
A square isothermal chip is of width w = 5 mm on a side and is mounted in a substrate such that its side and back surfaces are well insulated; the front surface is exposed to the flow of a coolant at t[infinity] = 15°c. from reliability considerations, the chip temperature must not exceed t = 85°c. f the coolant is air and the corresponding convection 200 w/m2 k, what is the maximum allowable chip power?
<u>ANSWER:</u>
The heat transfer through convection, we have the equation:
q = hA(T - T∞)
where,
q = power transfer through convection = ?
h = convection coefficient = 200 W/m²K
A = Area of convection surface = (0.005 m)² = 0.000025 m²
T = Chip surface temperature = 85° C
T∞ = Fluid temperature = 15° C
Therefore,
q = (200 W/m².K)(0.000025 m²)(85° C - 15° C)
<u>q = 0.35 W</u>
Since, difference in temperature is same on both Celsius and kelvin scale. Therefore, Celsius is written as kelvin for difference and they shall be cancelled.
