Waec 2017 Physics Obj and Theory Answers – May/June Expo

Waec 2017 Physics Obj and Theory Answers – May/June Expo

» Exam Time:

Physics 2 (Essay) 09.30am – 11.00am

Physics 1 (Objective) 11.00am – 12.15pm

ANswers WIll Be Posted By: 8:00am

PHYSICS OBJ

1BBCADAAABB
11BBDCBDCCCD
21ABCDCCCDAC
31ACCBCDAABC
41AADDAADBDC
===========
===========

SECTION A ANSWER 5 QUESTIONS
SECTION B ANSWER 3 QUESTIONS

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

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
===========

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

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
===========

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 the roy
==========

11ai)
A dielectric is an electrical insulator that can be polorised by an applied electric field.

(11aii)
Given that A = 9.6*10^-3M^2
d = 2.25*10^4
Eo = 8.85*10^-12 F/m
Er = 900
C = /
using; C = EoErA/d

Capacity, C = 8.85*10^-12*900*9.6*10^-3/2.25*106-4
C = 33984 * 10^-11
C = 3.3984 8 10^7 F
C =0.34#F

11bii)
Combined resistance RT
RT= (400*400)/400+400 = (800*800)/(800+800)
RT= 200+400
RT =600 ohms
Current supplied by battery = v/RT
= 6/600
=0.01A

Voltage drop across 400 ohm resistors
= 200*0.01
=2v

Therefore the voltmeter reading is
= 6 - 2
= 4v

(11c)
Equivalent resistance is:
RT = 2+2 +(2*2)/2+2
RT = 4+1
RT = 5 ohms
============

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)
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.

b)
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.

c)
Liquid sodium serves as coolant in a nuclear fission reactor.
==========


=====COMPLETED=====

=====KEEP REFRESHING EVERY 5MINS=====