Physics answer 2017 WAEC

3)
i)Brownian motion
ii)Atomic size
iii)Expansion
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2)
given that U=15m3^-1
R=U* sqr2h/g
h=20m
g=10
R=15*sqr2*20/10
R=15*sqr40/10
R=15*sqr4
R=15*2=30m
R=30m
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5a)
i)force
ii)length
5b)
by increasing the density mosquitoes lavrva than the density of water
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6)
i)Energy efficient- so far the best light for interior lighting
ii)Low production cost (of tubes, not of the ballasts)
iii)Long life of tubes
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12ai)
Nuclear fission is a nuclear reaction in which a heavy nucleus splits spontaneously or on impact with another particle, with the release of energy.
12aii)
A graphite reactor is a nuclear reactor that uses carbon as a neutron moderator, which allows un-enriched uranium to be used as nuclear fuel.
12aiii)
Boron rods are used in
nuclear reactors to control the fission rate of uranium and plutonium. They are composed of chemical elements such as boron, silver, indium and cadmium that are capable of absorbing many neutrons without themselves fissioning.
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8b)If their distance and masses are doubled their corresponding force would also be doubled and the work done respectively
I.e.Workdone=Force * distance
Force= Mass * Acceleration
W= Mg * d
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Increase
8d (i)pushing someone on a swing.
      (ii)Tuning a radio to a particular frequency.