
More Difficult Problems in Physics From post utme (Unilorin 2007)
Physics
Chima Sunday (Tutor)
08042016 10:18:00 +0000About 80% of people that tried solving these questions got it wrong. Try and see if you can have right
Question 10 The echo produced when a motion is fire from a ship some distance from cliff is heard 1.2 second. Calculate the distance of the ship (if the velocity of Sound in air = 330m/s)
Option A 138m
Option B 198m
Option C 275m
Option D 296mSolution
velocity v = 2d/t
so by subject formular 2d = vt
d = vt/2 = 330×1.2/2 = 189m
Answer is option BQuestion 8 The critical angle of glass is 42 degree, the approximate refractive index of this glass is
Solution
Option A 1.50
Option B 1.38
Option C 1.80
Option D 2.30
at critical angle n = 1/sinC
where C is the critical angle and n the refractive index,
thus n = 1/sin42 = 1/0.669 = 1.49 = 1.50
Answer is Option A

Arayemi Martins
formula for echoe=v=2x/t v=330ms^1,t=1.2s,x=? 330=2x/1.2 2x=330×1.2 2x=396 x=396/2 x=198m(b)
0 11052016 23:51:00 +0000

Chima Sunday (Tutor)
Thumb up to all of you that tried to solve this problem and also those that got it right @Damian Nonsy @Arayemi Martins and @Onyeaku Emmanuel.
Note that this post has been updated with its solutions.
Thanks.0 31052016 10:26:00 +0000

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