2017/2018 WAEC Physics Answer

Here is the 2017/2018 WAEC Physics Answers.


OBJ
1-10 CAABADACC
11-20 BAADDCBADA
21-30 CCBACBCBAB
31-40 ACADDBBBAC
41-50 BCDABCABCA



1)
decrease in height (h)
increase in time (t)
this shows that distance changes with time


3)
i)Brownian motion
ii)Atomic size
iii)Expansion.


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


4)
L1=14cm F1=4N,F2=6N
L2=4cm, Lo=?
Using hooke's law
4/14-Lo*6/4-Lo
4(4-Lo)=6(14-Lo)
16-4Lo=64-6Lo
-4Lo+6Lo=64-16
2Lo=48
Lo=48/2
Lo=24Cm


5a)
i)force
ii)length

5b)
by increasing the density mosquitoes lavrva than the density of water


6)
A)Energy efficient- so far the best light for interior lighting
B)Low production cost (of tubes, not of the ballasts)
C)Long life of tubes


7)
i)It requires low voltage sources for it to function
ii)It cannot be easily broken
iii)It is cheaper and quite easy to manufacture



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


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
|
Increase

8c)
-Acceleration due to gravity
- At maximum height, final velocity is zero

8d)
i)pushing someone on a swing.
ii)Tuning a radio to a particular frequency.


10a)
A wave front is an imaginary surface passing through the points of a medium oscillatory in phase
10b)
i)Priam periscope used in harmod car
ii)prismatic bihocular to see round corner
10bii)
i)refractive indege of the glass prism
ii)the angle of incident of th