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ziro4ka [17]
3 years ago
11

In a cellular phone system, a mobile phone must be paged to receive a phone call. However, paging attempts don’t always succeed

because the mobile phone may not receive the paging signal clearly. Consequently, the system will page a phone up to three times before giving up. If the results of all paging attempts are independent and a single paging attempt succeeds with probability 0.8, sketch a probability tree for this experiment and find the probability P[F] that the phone receives the paging signal clearly.
Engineering
1 answer:
Alina [70]3 years ago
7 0

Answer:

The correct response will be "0.992". The further explanation to the following question is given below.

Explanation:

The probability that paging would be beneficial becomes 0.8  

Effective paging at the very first attempted is 0.8

On the second attempt the success probability will be:

⇒  0.2\times 0.8

⇒  0.16

On the third attempt the success probability will be:

⇒  0.2\times 0.2\times 0.8

⇒  0.032

So that the success probability will be:

⇒  0.8 + 0.16 + 0.032

⇒  0.992

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Time = 30 minutes = 30*60 = 1800 seconds

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Rise in surface temperature = 8 °C after 30 minutes

Explanation:

The surface temperature of the aluminum block is given by

T_{surface} = T_{initial} + \frac{q}{k} \sqrt{\frac{4\alpha t}{\pi} }

Where q is the heat flux supplied to aluminum block, k is the conductivity of pure aluminum and α is the diffusivity of pure aluminum.

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T_{surface} = 26.5 + \frac{4000}{237} \sqrt{\frac{4(9.71\times 10^{-5}) (2112)}{\pi} }\\\\T_{surface} = 26.5 + \frac{4000}{237} (0.51098)\\\\T_{surface} = 26.5 + 8.6\\\\T_{surface} = 35.1\\\\

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Rise = 35.1 - 26.5 = 8.6 °C

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The rise in the surface temperature is

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Therefore, the surface temperature of the block will rise by 8 °C after 30 minutes.

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