PHY3703
ASSIGNMENT 2
FULL SOLUTIONS
COMPLETE SOLUTIONS
MEMORANDUM
UNISA
2026
Page 1 of 18
,SOLUTION:
(a) Fair Coin
1 1
Probability distribution: 𝑝1 = 2 , 𝑝2 = 2
2
𝑆 = − ∑ 𝑝𝑖 log2 𝑝𝑖
𝑖=1
Page 2 of 18
, 𝑆 = −(𝑝1 log2 𝑝1+𝑝2 log2 𝑝2 )
1 1 1 1
𝑆 = − (2 log2 2 + 2 log2 2)
1
Since log2 2 = log2 2−1 = −1:
1 1
𝑆 = − ( × (−1) + × (−1))
2 2
1 1
𝑆 = − ( − 2 − 2)
𝑆 = −(−1) = 1
𝑆 = 1 bit
(b) Biased Coin
1 4
Probability distribution: 𝑝1 = 5 , 𝑝2 = 5
2
𝑆 = − ∑ 𝑝𝑖 log2 𝑝𝑖
𝑖=1
𝑆 = −(𝑝1 log2 𝑝1+𝑝2 log2 𝑝2 )
1 1 4 4
𝑆 = − ( log2 + log2 )
5 5 5 5
1
Compute log2 5:
1
log2 = log2 5−1 = −log2 5
5
ln 5 1.609437912
log2 5 = ≈ ≈ 2.321928095
ln 2 0.693147181
Thus:
1
log2 ≈ −2.321928095
5
4
Compute log2 5:
Page 3 of 18
ASSIGNMENT 2
FULL SOLUTIONS
COMPLETE SOLUTIONS
MEMORANDUM
UNISA
2026
Page 1 of 18
,SOLUTION:
(a) Fair Coin
1 1
Probability distribution: 𝑝1 = 2 , 𝑝2 = 2
2
𝑆 = − ∑ 𝑝𝑖 log2 𝑝𝑖
𝑖=1
Page 2 of 18
, 𝑆 = −(𝑝1 log2 𝑝1+𝑝2 log2 𝑝2 )
1 1 1 1
𝑆 = − (2 log2 2 + 2 log2 2)
1
Since log2 2 = log2 2−1 = −1:
1 1
𝑆 = − ( × (−1) + × (−1))
2 2
1 1
𝑆 = − ( − 2 − 2)
𝑆 = −(−1) = 1
𝑆 = 1 bit
(b) Biased Coin
1 4
Probability distribution: 𝑝1 = 5 , 𝑝2 = 5
2
𝑆 = − ∑ 𝑝𝑖 log2 𝑝𝑖
𝑖=1
𝑆 = −(𝑝1 log2 𝑝1+𝑝2 log2 𝑝2 )
1 1 4 4
𝑆 = − ( log2 + log2 )
5 5 5 5
1
Compute log2 5:
1
log2 = log2 5−1 = −log2 5
5
ln 5 1.609437912
log2 5 = ≈ ≈ 2.321928095
ln 2 0.693147181
Thus:
1
log2 ≈ −2.321928095
5
4
Compute log2 5:
Page 3 of 18