2-m-long, 0.3-cm-diameter electrical wire extends across a room at 15°C, Heat is generated in the wire as a result of resistance heating, and the surface temperature of the wire is measured to be 152°C in steady operation. Also, the voltage drop and electric current through the wire are measured to be 60 V and 1.5 A, respectively. Disregarding any heat transfer by radiation, determine the convection heat transfer coefficient for heat transfer between the outer surface of the wire and the air in the room.

2-m-long, 0.3-cm-diameter electrical wire extends across a room at 15°C, Heat is generated in the wire as a result of resistance heating, and the surface temperature of the wire is measured to be 152°C in steady operation. Also, the voltage drop and electric current through the wire are measured to be 60 V and 1.5 A, respectively. Disregarding any heat transfer by radiation, determine the convection heat transfer coefficient for heat transfer between the outer surface of the wire and the air in the room.

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

Consider a double-paned window consisting of two panes of glass, each with a thickness of 0.500 cm and an area of 0.795 m2 , separated by a layer of air with a thickness of 1.50 cm. The temperature on one side of the window is 0.00 ∘C∘C; the temperature on the other side is 21.0 ∘C∘C. In addition, note that the thermal conductivity of glass is roughly 36 times greater than that of air. Approximate the heat transfer through this window by ignoring the glass. That is, calculate the heat flow per second through 1.50 cmcm of air with a temperature difference of 21.0 ∘C∘C. (The exact result for the complete window is 25.6 J/sJ/s .)
Determine the heat flow (in Watts) across a plane wall of 8.1m thickness with a constant thermal conductivity of 9.67 W/mK when the surface temperatures are steady at 422°C and 73.5°C. The wall area is 29m². Reduce your answer into two decimal places. T, -L-
Consider a person standing in a room kept at 22°C at all times. Your house It has been observed that the inner surfaces of the walls, floor and ceiling are at an average temperature of 15°C. If this person's exposed surface area is 1.4 m2 and if the average external surface temperature is 30°C, this person and the surrounding surfaces Determine the radiation and heat transfer rate between One's emissivity, the Stefan-Boltzmann constant a=5,67x10 -8 W/m 2 K 4
A 20-cm diameter copper ball is to be heated from 110°C to an average temperature of 170°C in 90 minutes. Taking the average density and specific heat of copper in this temperature range to be p=8950 kg/m and Cp=0.395 kJ/kg • °C, respectively, determine the total amount of heat transfer to the copper ball in kj (Area of sphere: TID2; Volume of sphere=TTD/6)? A 88.64 kJ B 886.4 kl 78.84 kJ D 788.4 kJ
Q2/ Consider a 1.2-m-high and 2-m-wide glass window whose thickness is 6 mm and thermal conductivity is k = 0.78 W/m. °C. Determine the steady rate of heat transfer through this glass window and the temperature of its inner surface for a day during which the room is maintained at 24°C while the temperature of the outdoors is 5°C. Take the convection heat transfer coefficients on the inner and outer surfaces of the window to be h1 = 10 W/m2 °C and h2= 25 W/m2 °C, and disregard any heat transfer by radiation.
An ice chest whose outer dimensions are 30 cm*40 cm*40 cm is made of 3 cm thick Styrofoam (k = 0.033 W/m°C). Initially, the chest is filled with 30 kg of ice at 0 °C, and the inner surface temperature of the ice chest can be taken to be 0 °C at all times. The heat of fusion of water at 0 °C is 333.7 kJ/kg, and the surrounding ambient air is at 20 °C. Disregarding any heat transfer from the 40 cm*40 cm base of the ice chest, determine how long it will take for the ice in the chest to melt completely if the ice chest is subjected to (a) calm air and (b) winds at 30 km/h (assume the heat transfer coefficient on the front, back and top surfaces to be the same as that on the side surfaces). Use the thermophysical properties of air as follows: k = 25.5×10-3 W/mK, ν = 15×10-6 m2/s, α = 21.1×10-6 m2/s, and β = 3.43×10-3 K-1.
A plane wall 3.5 cm thick generates heat internally. The wall is made of a material with thermal conductivity of 44 W/m K. Both faces of the wall are maintained at 50.30°C. If the maximum temperature inside the wall is 61°C, what is the rate of internal heat generation in the wall per unit volume? Express your answer in W/m³.
Question 2:A circuit board houses on its surface120 closely spaced logic chips, each dissipating 0.12 W. If theheat transfer from the back surface of the board is negligible, calculate (a) the amount of heat this circuit board (15 cm x20 cm) dissipatesduring a 10-hour period, in kWh, and (b) the heat flux on thesurface of the circuit board, in W/m2
An electrical wire with 0.4cm in diameter and 2.5m long extends across a room with 15deg C temperature. Heat is generated in the wire as a result of resistance heating, and the surface of the wire is measured to be 162degC. the voltage drop and electric current along the wire is 60V and 1.64 A, respectively. Determine the convection heat transfer coefficient for the heat transfer between the surface of the wire and the room air. Hint, electric power formula. Round your answer to 2 decimal places.
It is measured that a 2-m2 wall has a heat transfer rate of 7200 W. If the thickness of the wall is 0.02-m and the temperature difference on either side of the wall is 60ºC, determine the thermal conductivity in W/m K.
1- Consider a 1 m high and 2 m wide glass window whose thickness is 8 mm and thermal conductivity is k =0.68 W/m°C. Determine the steady rate of heat transfer through this glass window and temperature of its inner surface for a day during which the room is maintained at 22 °C while the temperature of the outdoors is -3 °C. Take convection heat transfer coefficients on the inner and outer surfaces of the window to be h, = 15 W/M2°C and h, = 20W/m°C .r