An electrical device is insulated on all sides except one face. That face is bonded to a 4mm thick aluminum plate which is cooled by air. The electrical device dissipates 10^4 W m2 The resistance of the joint between the device and aluminum plate is 0.5E-4 m2K W The conductivity of the aluminum is 238 W mK The temperature of the air is 278 K and the convection coefficient from the aluminum plate to the air is 100 W m2K What is the operating temperature of the device
Answer:
t₁ = 378.668 K
Explanation:
From the given information:
The heat dissipated (q) from the electrical device = [tex]10^4 W/m^2[/tex]
The contact resistance between device and aluminium;
(R_{const} ) = 0.5× 10⁻⁴ m² K/W
Conductivity of aluminum (k) = 238 \ W/mK
The thickness of aluminum plate (L) = 0.004 m
Convection coefficient (h) = 100 \ W/m^2 K
Surrounding temperature (t_2) = 278 \ k
According to Fourier's law of heat conduction.
[tex]q = \dfrac { t_1- t_2 }{R_{const} + \dfrac{L}{k} + \dfrac{1}{h} }[/tex]
[tex]10^4 = \dfrac{t_1 - 278}{0.5 \times 10^{-4} + \dfrac{0.004}{238} + \dfrac{1}{100} }[/tex]
[tex]10^4 *( 0.5 \times 10^{-4} + \dfrac{0.004}{238} + \dfrac{1}{100}) = t_1 - 278[/tex]
[tex]100.668 = t_1 -278[/tex]
t₁ = 378.668 K
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True or False?
true
the answer to this question is true
Drag the 100 n block onto the diaphragm spring and use the ruler to measure the compression how many meters has the spring compressed?
why data structure is important
Answer:
Data structures are important as it allows the user to insert, update, arrange, rearrange, delete, and retrieve data in an efficient manner, from the database. And to accomplish the said tasks algorithms are used. It is used to manipulate the stored data within the database in the required manner. …
Explanation:
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The doorbell of a home requires 10 volts to operate. A transformer is used to connect a 120 v primary circuit within the home to the doorbell. The transformer in the doorbell has 500 turns on the primary coil and supplies the doorbell with 900 mA of current.
Required:
a. Determine whether the transformer features a step-up or step-down design.
b. Calculate the number of turns on the secondary coil.
c. Calculate the current that is drawn from the 120-V household circuit to operate the doorbell in mA.
Answer:
See explanation
Explanation:
a) The transformer must be a step down transformer because the secondary voltage which it supplies is less than the primary voltage.
b) From;
Ns/Np = Es/Ep
Where;
Ns= number of turns in secondary coil
Np= number of turns in primary coil
Es= voltage in secondary coil
Ep= voltage in primary coil
NsEp = EsNp
Ns = EsNp/Ep
Ns = 10 * 500/120
Ns = 42 turns
c) From;
Es/Ep = Ip/Is
EsIs = EpIp
Ip = EsIs/Ep
Ip = 10 * 900 * 10^-3/120
Ip = 75 mA
1. The hull of the space shuttle consists of ceramic tiles bonded to an aluminum skin. Discuss the design requirements of the shuttle hull that led to the use of this combination of materials. What problems in producing the hull might the designers and manufacturers have faced
Answer:
Follows are the solution to the given question:
Explanation:
In the environment of the piles of earth, its spacecraft faces extreme temperatures:
Therefore, to prevent satellite build sustainability, a temperature control system must be used.
Its skin must be rather permeable in physiological terms.
Its shuttle's surface should have adhered to both the material well.
Whether it gets broken, it ought to be easy to repair.
All tile mostly on the cutter is composed of silicon dioxide particles, that are bonded and create a tile of very low density.
Its heat transfer is so small that even a person may hold a burning hot side on one side of the tile.
Skin that uses a rubber resin to ensure that perhaps the powers may not release the cutting that heat-treated will then the internal body.
The design requirements that led to the combination of ceramic tiles and aluminium materials for the hull of shuttle space are; discussed below.
The space shuttle experiences extreme temperatures during re-entry into the earths atmosphere. Thus, as a result, a thermal protection system must be provided to help prevent damage of the shuttle structure.
Therefore, the skin must be made up of material that has an exceptionally low thermal conductivity and also the material must be able to be firmly attached to the skin and also be able to be easily repaired in case of any damage.
Secondly, the tiles used on the space shuttle will have to be composed of silica fibers that are bonded together to generate a ceramic of low density. The thermal conductivity of the ceramic would have to be low such that if you touch one end while the other is very hot, you will not feel the hotness.
Now, the tiles will be attached to the shuttle skin with the aid of a rubbery polymer which ensures that the forces don't break the tile loose which will then expose the underlying skin to high temperatures.
Read more about some physical properties of ceramic at; https://brainly.com/question/14215109
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