2018 waec physics answer

Physics OBJ:
1CADBACBADC
11ADBDDABDCC
21DBAABAACAD
31DCBBCCBABB
41BDCDDACADC

(i) / means division or divide
Examples:
2/2 means 2/2 ie 2 over 2.
—————–
(ii) * means multiplicat i on
Example: 2*2 means 2×2
—————–
(iii) ^ means Raise to power
—————–
(iv) Sqr root means means square root sign ie _/
SECTION A ANS 5QUESTION
================================
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
========================
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 part i cular frequency.
SECTION B ANS 3 QUESION
================================
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.

Keep reloading page every 5, 5minutes interval

Staytune!!!