Answer: the thermal conductivity of the sample is 22.4 W/m . °C
Explanation:
We already know that the thermal conductivity of a material is to be determined by ensuring one-dimensional heat conduction, and by measuring temperatures when steady operating conditions are reached.
ASSUMPTIONS
1. Steady operating conditions exist since the temperature readings do not change with time.
2. Heat losses through lateral surfaces are well insulated, and thus the entire heat generated by the heater is conducted through the samples.
3. The apparatus possess thermal symmetry
ANALYSIS
The electrical power consumed by resistance heater and converted to heat is:
Wₐ = V<em>I</em> = ( 110 V ) ( 0.4 A ) = 44 W
Q = 1/2Wₐ = 1/2 ( 44 A )
Now since only half of the heat generated flows through each samples because of symmetry. Reading the same temperature difference across the same distance in each sample also confirms that the apparatus possess thermal symmetry. The heat transfer area is the area normal to the direction of heat transfer. which is the cross- sectional area of the cylinder in this case; so
A = 1/4πD² = 1/3 × π × ( 0.05 m )² = 0.001963 m²
Now Note that, the temperature drops by 15 degree Celsius within 3 cm in the direction of heat flow, the thermal conductivity of the sample will be
Q = kA ( ΔT/L ) → k = QL / AΔT
k = ( 22 W × 0.03 m ) / (0.001963 m² × 15°C )
k = 22.4 W/m . °C
Answer:
The correct answer is letter "C": Both.
Explanation:
Industrial seals are used at interfaces between components to prevent leakage, to maintain heat, and to avoid contamination. The design, construction, and materials they use vary depending on industrial use but the most common are Polytetrafluoroethylene (PTFE), Nitrile Buna Rubber (NBR), and fluorocarbon.
Thus, using a sharp chisel could pry a seal out of a hole and a regular socket can often be used to force smaller metal-backed seals into place. Thus, technicians "A" and "B" are correct.
The absolute pressure in psia being measured is; 27.228 psia
<h3>What is the absolute Pressure?</h3>
Formula for absolute Pressure is;
Absolute pressure = Atmospheric pressure + Gauge pressure
P_{abs} = P_{atm} + P_g
We are given;
P_atm = 29.86 (in Hg) = 14.666 psia
Density of mercury at 70 °F; ρ = 13.543 g/cm³
Mercury Manometer reading; h = 25.62 in
Acceleration due to gravity; g = 32.243 ft/s²
Gauge pressure of the mercury = ρgh = 13.543 * 25.62 * 32.243
When we multiply and covert to psia gives; P_g = 12.562 psia
Thus;
P_abs = 14.666 + 12.562
P_abs = 27.228 psia
Read more about Absolute Pressure at; brainly.com/question/17200230
