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Suppose you flip 20 fair coins.

(a) How many possible outcomes (microstates) are there?

(b) What is the probability of getting the sequence HTHHTTTHTHHHTHHHHTHT (in exactly that order)?

(c) What is the probability of getting 12 heads and 8 tails (in any order)?

Short Answer

Expert verified
(a)The possible outcomes microstate are1048576microstates

(b) The probability of getting the sequence isP=9.536107

(c)The probability of getting 12 heads and 8 tails areP=0.12

Step by step solution

01

Step1:possible outcome of macrostate(part a)

(a)We suppose we flip 20 coins, n=20. The total number of microstates will be:

Calculation method

2n=220

=1048576microstate

So, the answer is 220or 1048576 microstates.

02

Step2:The probability of sequence(part b)

(b)The likelihood of obtaining any specific sequence of heads and tails (for example HTHHTTTHTHHHTHHHHTHT) is

P=Favorable microstateTotal number of microstates

=12n=1220

=11048576

=9.536107

As a result, the answer is for the sequence of heads and tails. (for example HTHHTTTHTHHHTHHHHTHT) is 1220or 9.53610-7.

03

Step3:Probability of 12 heads and 8 tails(part c)

(c)Regardless of order, the probability of getting the macrostate of 12 heads and 8 tails is given by:

P=NnTotal number of microstates

where n denotes the number of heads and N denotes the number of coins, so:

P=20121048576

After arranging we get,

2012=20!12!(2012)!=125970

Finally solution is

P=1259701048576=0.12

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Most popular questions from this chapter

Consider an ideal monatomic gas that lives in a two-dimensional universe ("flatland"), occupying an area Ainstead of a volume V. By following the same logic as above, find a formula for the multiplicity of this gas, analogous to equation 2.40.

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