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PHYSICS (OBJ & ESSAY) 2015 NECO GCE FREE EXPO






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Tuesday 10th Nov. 2015
PHYSICS (OBJ & ESSAY)
2.00PM-5.00PM.
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COMPLETE Physics OBJ:
1babdaecdeb
11cdadddbcbb
21dbebbeaceb
31ebebcbccda
41bdbcedaaae
51aaabbaceca


(1a) An artificial satellite whose orbit is synchronized with that of the earth, so that it remains fixed over the same spot above the planet at all times.

(1b)
-earth quake
-flood

(1c)
a=v/r
10=v/4*10^4 km
10=v/4*10^7
v=4*10^8 m/s
(2a)
Centripetal and centrifugal forces


(2b)
V=wr


==================================

(3ai)
Throwing a javelin

(3aii)
Shooting of an arrow

(3b)
Vsin*tita
S=(v+u/2)t
S=1/2at^2
7.2=1/2*10*t^2
1.44=t^2
t=sqroot1.44
=1.2s

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(4a)
E=MA/VR*100%
E=efficiency
VR=Velocity ratio
MA=Mechanical advantage

(4b)
60%=MA/4*100
MA/4=0.60
MA=2.4
MA=load/effort
2.4=200/effort
=83.3N

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(6a)
Differences: Light waves can be polarised while water waves cannot be polarised

Similarities: Both light and water waves possess frequency and wavelenght

(6b)
-Infra-red rays are used as electromagnetic waves as vitamin D

-Infra red rays are needed by plant for photosynthesis


(13a)
Specific latent heat of fusion is the quantity of heat energy need to convert a mass 1kg of a body from ice to liquid without a change in temperature

(13bi)
Conventional current can be defines as the flow of electrons through the circuit and into the negative terminal of the source

(13bii)
Practical application:
-For correcting change in electron flow
-For creating electrons for positive terminals

(13c)
Mass of water=500g=0.5kg
MC(change in tita),ML
0.5*4.2*10^3*100=[(0.5+x)*3.2*10^5]
210000=1.6*10^5+3.2*10^5x
50000=3.2*10^5x
x=50000/3.2*10^5
x=0.16kg
x=1600g


15 a) Newtons Law of Universal Gravitational States that ' Every particle in rhe universe attracts every other particle with a force , that is proportional to the product of their masses and inversely proportional to the square of the distance between them

15 b ) i . Eddy Currents
ii . Hysteresis Loss



12ai)

static friction is the maxium force that must be over come before a body can just start to move over another while dynamic friction is the force that must be overcome so that the body can move with uniform speed over another body


12aii)

a) without friction it will be impossible to walk it also help in moving body to come to rest

b)friction is used in the grindstone to sharpen knives clisels and other object


12ci)

a=dv/t

1.7=v/10

v=1.7*10=17ms^1


12cii)

a=DV/T=Da a2-a=17-0.3=1.4m/s^2

1.3=v/20

v=1.3*20=26m/s


(16ai)
Radioactivity is the spontaneous disintegration of the nucleus of the atom of an element during which it emits &-, B- particles or X-rays or a combinatiom of any or all of the three, and energy.

(16aii)
Natural Radioactivity is the Spontaneous desintegratiom of the nucleus of an atom during which particles or rays and heat are released while in artificial radioactivity, an ordinary material that is not normally radioactive is made radioactive by bombarding it with radioactive particles.

(16bi)
1. The Bohr Model
2. Rutherford Planetary model

(16ci)
Wo = hf - Emax
Wo = (6.6 x 10^-34 x 8.5x10^14) - 3.4 x 10^-19
Wo = (5.61 x 10^-19 - 3.4 x 10^-19)J
Wo = 2,21 x 10^-19J

(16cii)
Wo = hf - Emax
Emax = hf - Wo
--> 4.1 x 10^-19 = 6,6 x 10^-34 x f - 2.2 x 10^-19
6.6 x 10^-34 x f = 4.1 x 10^-19 + 2.21 x 10^-19 = 6.3
f = 6.31 x 10^-19/6.6 x 10^-34 = 0.956 x 10^15HZ
= 9.56 x 10^14HZ



(14ai)
Hearing aid is an electroacoustic device whic is designed to amplify sound for the wearer,usually the aim of making speech more intelligible and to correct impaired hearing

(14aii)
-Body worn aids
-Behind hear aids

(14aiii)
-To correct problems related to hearing
-it makes speech more audible for hearing impaired people

(14b)
Y=Asin[2*pie*f*t+2*pie*x/landa]
Y=0.2sin[22*pie*t-10*pie*x/4]

(i)
22*pie*t=2*pie*f*t
22=2f
f=11hz

(ii)
10*pie*x/4=2*pie*x/landa
landa=4/5=0.8m
V=f*landa
V=11*0.8=8.8m/s
Y=0.4sin[220*pie*t+10*pie*x/4]












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Posted By KellyChi On 01:37 Tue, 10 Nov 2015

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