
Common Questions Asked in Post UTME Physics Exams. Day1
Physics
Chima Sunday (Tutor)
25052016 16:51:00 +0000The first question is on topic9 and the second question is from topic11. Try your best to solve them. Show working on paper and include a picture of your hand written Solution in your response. Happy Solving!
1. Three 4Ω resistors were connected in series by Tola while Ade connected the same set of resistors in parallel. The ratio of the value obtained by Ade to that obtained by Tola is
A. 1:2
B. 1:9
C. 1:10
D. 1:5
( O.A.U. 2006)Solution
In series connection by Tola
Effective resistance R_{T} = 4 + 4 + 4 = 16Ω
In parallel connection by Ade
effective resistance is given by 1/R = 1/4 + 1/4 + 1/4 = 3/4Ω
therefor R_{A} = 4/3 Thus ratio = Ade : Tola = 4/3 : 12
multiplying both side by 3/4 i.e =4/3*3/4 : 12*3/4 = 1 : 9
Answer is option B2. In a nuclear fusion experiment, the loss of mass amount to 1.0×10^{5}kg the amount of energy obtained from the fusion is?(speed of light = 3×*10^{8}m/s)
. A. 3*10^{4}J
B. 3*10^{11}J
C. 9*10^{4}J
D. 9*10^{11}J
(UNN 2006/2008)Solution
From Einstein energy and mass relation E = mc^{2}
Where c is the speed of light
So m = 1.0×10^{5}kg
E = 1.0×10^{5} × (3×*10^{8})^{2}
so that E = 9 *10^{11}J
So Answer is D

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