plz solve these questions soon exam on this thurday

Question No.1: The star Alpha Centauri is nearest to the Sun and its distance is 4.3 light-years.
(a) How much is its distance in parsecs? (I got this answer.)
(b) What is the annual parallax angle? (Didn’t get this answer)
(c) How much time will light take to travel from the star to us? (Didn’t get this answer too)
(Given- The distance from the Earth and the Sun = 1.496*10^11 metres.)
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Question No.2: the Young’s Modulus Y is determined by stretching a wire by using the formula
Y= (4FL)/(pie*d^2*l)
Where F is stretching force , L is length of the wire , l is extension in length and d is diameter . If F is of the order 500N and known to 1 part in 1000, L of the order 3m and measured with an accuracy of 1mm , l is of the order 5mm measured to 0.1 mm and d is of the order 1mm measured correct upto 0.01mm, estimate the percentage error in the measurement of Y. [Hint Given : % error in F is 0.1 %]
Please solve and reply soon coz I have exams on Thursday.