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marishachu [46]
3 years ago
6

An aluminum heat sink (k = 240 W/m-K) used to cool an array of electronic chips consists of a square channel of inner width w =

30 mm, through which liquid flow may be assumed to maintain a uniform surface temperature of T1 = 25 °C. The outer width and length of the channel are W = 50 mm and L = 200 mm, respectively.
If N = 100 chips attached to the outer surfaces of the heat sink maintain an approximately uniform surface temperature of T2 = 60 °C and all of the heat dissipated by the chips is assumed to be transferred to the coolant, what is the heat dissipation per chip? If the contact resistance between each chip and the heat sink is R12 = 0.2 K/W, what is the chip temperature?

Engineering
2 answers:
OverLord2011 [107]3 years ago
8 0

Answer:

Explanation: see attachment below

forsale [732]3 years ago
8 0

Answer:

The answers to the question are;

The heat dissipation per chip is 84 W

The chip temperature is 76.8 ° C

Explanation:

T1 = 25 °

T2 = 60°

ka = 240 W/(m×k)

The formula for heat transferred by conduction is given by

Q = (ka×A×(T1-T2))/La

Area A is given by

A = Length×Width = 50 mm × 200 mm = 10000 mm^2 = 0.01 m^2

La = (Outer width - Inner width)/2 = (50 mm - 30 mm)/2

= 10 mm = 0.01 mm

Therefore Q = (240×0.01×(60-25))/0.01 = 8400 W

Heat dissipated per chip = Q/N = 8400 W/100

= 84 W

Contact resistance is given by

Rcontact = (T3-T2)/(Q/A)

Where Q/A is the heat dissipated per each chip

Therefore

0.2 K/W = (T3-60)K/84

Or 84×0.2 = 16.8 = T3 - 60

T3 = 60 + 16.8 = 76.8 ° C

The chip temperature = 76.8 ° C

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PythonA group of statisticians at a local college has asked you to create a set of functionsthat compute the median and mode of
skelet666 [1.2K]

Answer:

  1. def median(l):
  2.    if(len(l) == 0):
  3.       return 0
  4.    else:
  5.        l.sort()
  6.        if(len(l)%2 == 0):
  7.            index = int(len(l)/2)
  8.            mid = (l[index-1] + l[index]) / 2
  9.        else:
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  20.    sum = 0
  21.    for x in l:
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Firstly, we create a median function (Line 1). This function will check if the the length of list is zero and also if it is an even number. If the length is zero (empty list), it return zero (Line 2-3). If it is an even number, it will calculate the median by summing up two middle index values and divide them by two (Line 6-8). Or if the length is an odd, it will simply take the middle index value and return it as output (Line 9-10).

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In mean function,  after checking the length of list,  we create a sum variable and then use a loop to add the item of list to sum (Line 23-25). After the loop, divide sum by the length of list to get the mean (Line 26).

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3 0
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Answer:

Circuit attached with explanation

Explanation:

Hi Dear,

A circuit is attached for your reference.

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Hope this finds easy to you.

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