- kA).. 4. Which of the following expresses thermal diffusivity of a substance in terms of thermal conductivity(k), density (p) and specific heat (Cp) A. p.k.Cp C. 1/ p.k.Cp В. К/р.Ср D. p.Cp /k? 5. The boundary condition of the end insulated fin are: dT В. - kA), = 0 and T=To at x=0 dT - kA() =0 and T=To at x=L dx A. dx C. T=0 at x=0 and q=0 at x=L D. None of them

- kA).. 4. Which of the following expresses thermal diffusivity of a substance in terms of thermal conductivity(k), density (p) and specific heat (Cp) A. p.k.Cp C. 1/ p.k.Cp В. К/р.Ср D. p.Cp /k? 5. The boundary condition of the end insulated fin are: dT В. - kA), = 0 and T=To at x=0 dT - kA() =0 and T=To at x=L dx A. dx C. T=0 at x=0 and q=0 at x=L D. None of them

Elements Of Electromagnetics

7th Edition

ISBN:9780190698614

Author:Sadiku, Matthew N. O.

Publisher:Sadiku, Matthew N. O.

ChapterMA: Math Assessment

Section: Chapter Questions

Problem 1.1MA

See similar textbooks

Similar questions

Give True or False for the following: 1.In liquids and gases, heat transmission is caused by conduction and convection 2.The surface geometry is the important factor in convection heat transfer 3. The heat transfer by conduction from heated surface to the adjacent layer of fluid, 4. The heat transfer is increased in the fin when &> 1 5.The unit of the thermal diffusivity is m²/s 6. Temperature change between the materials interfaces is attributed to the thermal contact resistance 7. A material that has a low heat capacity will have a large thermal diffusivity. 8. Heat conduction flowing from one side to other depends directly on thickness 9.Fin efficiency is the ratio of the fin heat dissipation with that of no fin 10.The critical radius is represented the ratio of the convicted heat transfer to the thermal conductivity
a. A slab of thermal insulator is 100 cm² in cross section and 2 cm thick. Its thermal conductivity is 2.4 x 10 -+ cal/(s cm C"). If the temperature difference between opposite faces is 180 F', how much heat flows through the slab in one day?
To maximize production and minimize pumping costs, crude oil is heated to reduce its viscosity during transportation from a production field. (1) Consider a pipe-in-pipe configuration consisting of concentric steel tubes with an intervening insulating material. The inner tube is used to transport warm crude oil through cold ocean water. The inner steel pipe (k, = 45 W/m-K) has an inside diameter of D;, 1 150 mm and wall thickness f; = 20 mm while the outer steel pipe has an inside diameter of D; 2 = 250 mm and wall thickness t, = tị. Determine the maximum allowable crude oil temperature to ensure the polyurethane foam insulation (k, between the two pipes does not exceed its maximum service temperature of Tp. max = 70°C. The ocean water is at T.0 = -5°C and provides an external convection heat transfer coefficient of h. flowing crude oil is h; = 450 W/m²-K. 0.03 W/m-K) 500 W/m2-K. The convection coefficient associated with the (2) It is proposed to enhance the performance of the…
The rate of heat flow equation is Q O A. Thermal resistance OB. Thermal coefficient O C. None of these OD. Thermal conductivity Type here to search KA(T₁-T₂) X E The term X ΚΑ is known as 99+
TRUE OR FALSE 4.) Bioyield is considered an elastic state and is located within the proportional limit 5.) The difference in the effect of temperature on viscosity of liquids and gases is related to the difference in their density. 6.) The parallel method of thermal conductivity calculation is based on the weighted harmonic mean of the components
Jes 1:01 i docs.google.com/forms what is the Physicists recognize four fundamental forces.* Flectrical force O - Gravitational force -Strong nuclear force Weak nuclear force O -Muscular force Force of friction Ff is described by • Ff = µN * O p synovlal fluld in the Joints P -coefficient of fraction between two surface in The temperature of the human body is normally about 98.6°F.calculate the temperature of the body "C* oC = (5/9)x(oF-32) =5/9(98.6- 32)-37 oc oc=(9/5)x(of -32) =9/5(98,6-32) =13,3 Under resting conditions the body energy is being used as follows * O 27% by the liver and splee O 20-%by the skeletal musules Under resting conditions the body energy is being used as follows. O 19% by the brain. 15% by the kidney. We can write the first law of thermodynamics as: * O AU-AQ -A.. O AU-AQ +AW. 1kcal = J O 1 Kcal =4184j. O O O O
Conduction Heat Transfer X material (a) material (b) . both (a) and (b) have the same thermal conductivity the temperature distribution is independent of thermal conductivity it's not that simple 9. Fin efficiency is defined as: • tanh (mL) (hP/k Ac)1/2 (heat transfer with fin) / (heat transfer without fin) (actual heat transfer through fin) / (heat transfer assuming all fin is at T = Tb) (Tx=L-Tf)/(Tb-Tf) 10. For an infinite fin, the temperature distribution is given by: (T-Tf)/(Tb-Tf)= e-mx. The heat flow through the fin is therefore given by: k (Tb-Tf)/L ● zero, because the fin is infinite ● infinite because the fin is infinite ● (Tb-Tf) (hP/k Ac)1/2 ● (Tb – Tf) (h P / k Ac)1/2 tanh (mL) 11. The Biot number, Bi, is defined as: • Bi=hk/L • Bi=hL/k • Bi= k/LH • Bi=qL/k • Bi=p UL/k 12. For a plate of length L, thickness, t, and width, W, subjected to convection on the two faces of area L x W. What is the correct length scale for use in the Biot number? . L ● W ● t • t/2 • L/2 13. If Bi…
Use for the ice? List all sumptions. 1.4 Consider axial flow of water in a cold tube. Write the heat conduction equation for the ice forming axisymmetrically on the inside surface of the tube. ice water 1.5 Consider two-dimensional conduction in the semi-circular cylinder shown. The cylinder is heated with uniform pe here to search 05:48 A qu) * ENG r-ny-E/-F hp
1 of 12 > 0/1 View Policies Show Attempt History Current Attempt in Progress X The sum of the second derivatives is zero for some values of a and b. The partial differential equation for two- dimensional steady-state conduction assuming no volumetric thermal energy generation and constant properties is + = 0 dx? dy? The following temperature distribution is valid under the stated conditions. T = ax + by True. False. True if a = -b. O It is not possible to determine whether the profile is valid. II
The amount of heat conducted through a wall of length r is given by Fourier's Law:. CONDUCTION RATE EQUATION T FOURIER'S LAW q, = -k A dT dx T, >T, where q, is the heat flux, k is a proportionality factor, Ais the wall's cross-sectional area, and 4 is the temperature gradient throughout the wall. Our friend Matt Labb wants to find T2 (temperature of the wall's rightmost edge) given q,, k, and A. Is this possible? If so, briefly explain how to find Tp. If not, briefly explain why.
Qi: (50 marks) Find the total heat flux of the composite wall when: B KA = KC = KF = 15 m. K KB = KD = 10 m. K KE = KG = 20 %3D m. K D. Height of B = C = D 4 cm 3 cm 4 cm 6 cm Height of F = G AT = 30 K
4. For a particular thermocouple, if one junction is maintained at 0°C (cold junction) and the other junction is used as a probe to measure the desired Celsius temperature t, the voltage V generated in the circuit related to the temperature t as V = t (a + bt) Further, for this thermocouple, when V is in millivolts, the two constants are a = 0.25 and b = -5.5 x10+. Determine the value of V if the measured temperature is 100°C.