NECO 2016 RUNz

NECO 2016
PHYSICS ANSWERS
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PHYSICS OBJ:
1-10 BABDAECDEB
11-20 CDADDDBCBB
21-30 DBEBBEACEB
31-40 EBEBCBCCDA
41-50 BDBCEDAAAE
51-60 AAABBACECA
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1a)
i) Rockets are used for space travels.
-Some rockets are used for war.
ii.)
-Satellites are used to get pictures of space that you can't
get on earth because of the clouds and atmosphere.
-Satellites are used to give a detailed description of the
weather.
1b)
A dam works when a Hydro power plant capture the energy
of falling water to generate electricity. A turbine converts
the kinetic energy of falling water into mechanical energy.
Then a generator converts the mechanical energy from the
turbine into electrical energy.
2a)
DRAW THE DIAGRAM
i)distance covered =5 m + 10m =15 m
ii )magnitude of his displacement
=a ^ 2= b^ 2 +c ^ 2
x ^ 2= 5^ 2 +10 ^ 2= 25
+100
x ^ 2= 125
x =sqr125
=5 sqr5m
4a)
i)pulley
ii )the inclined plane
4b)
veiw the digrams load ---- -- fulcrum ----- - effort eg-
crowbar
5)
V 1= 700 cm ^ 3 , T 1= 30dgree -census+273 =303 k , P 1=
606 mmHg
V 2= 700 -300 = 400 cm ^ 3 , T 2= 47+ 273 =320 k
from general gas law
P 1V 1 / T1 = P 2V 2 / T2
606 700 / 303 =P 2 400 / 320
P 2= 606 700 320 / 303 * 400
P 2= 1120mmHg
6a)
i. Sound waves can be heard by the ear because their
frequency is high enough to hear. While Radio waves are
much longer frequency waves and need electronics to see
or hear them.
ii. Sound waves are produced by oscillations of the air
while radio waves are oscillations of photons of light.
6b)
1. Using them as lenses, or coating lenses on sunglasses
reduces glare, without affecting chromatic integrity (i.e.
without adding a colour).
8a)
Electric current is the rate of charge flow past a given
point in an electric circuit , measured in Coulombs /
second which is named Amperes .
8b)
d= 30cm , £= 1. 5* 10 ^ -5 c r=30 cm
30 / 100 =0 .3 m
V =kE / r=9 * 10 ^ 9* 1.5 * 10 ^ -5 / 0. 3
=13 .5 * 10 ^ 4
=13 .5 * 10 ^ 5/ 3
V =4 .5* 10^ 5
V =450 kv
9a)
i)by heating
ii )electrical method
9b)
Energy stored in a capacitor
E= ½cv²
=½×4×800²
=2×640000
=1280000J
Therefore energy stored = 1280KJ or 1.2MJ
11)
TABULATE
-Hard Xray-
i)high penetrating power
ii )short wave length
iii )produce high voltage
-soft Xray-
i)low penetrating power
ii )long wave length
iii )produced at low voltage
(12a)
centre of gravity can be define as the point through which
the line of action of the weight of the body always passes
irrespective of the position of the body.
12b)
C.g = centre of gravity
:- v= u - gt
Of maximum height v=O - K
O= u-gt
For vertical component,
U =uSin tita
Therefore O= usin tita- gt gt =uSin tita
T=uSin tita/g
Where T is the time taken to maximum height
12c)
Taken moment about point A
Cwm = {60*10)+ (20*60)
Cwm=600+1200
Cwm=1800
Acwm = (20*40) + (R3 * 40)
Acwm=800+80R3
At equilibrium,
Cwm=Acwm
1800=800+40r3
1800-800=40r3
1000=40r3pqq
R3=1000/40
R3=25N
13a)
dew point is the temperature at which the water vapour
present in the atmosphere is just sufficent to saturate it
13b)
mist is formed as a result of condensed drops of moisture
throughout the mass of cooled air. That is when water
droplet in the air cool suddenly
13ci)
the plastic comb will acquire electric charges
13cii)
the plasic com can attract small pieces of paper due to
the acquired charges.
13di)
area expansivity(B)=2§
=2*1.2*10^-5
B=2.4*10^-5 1k
13dii)
given that initial length=6cm initial area
A=6*6=36cm^2
rise in temperature =25k linear expansivity=1.2*10^-5/k
area expansivity
=2.4*10^-5/k
new area At=Ao(1+Btita)
At=36(1+2.4*10^-5*25)
At=36(1+ 60*10^-5)
At=36(1+0.0006)
At=36(1.0006)
At=36.0216
15a)
electrical potential is the work required to transfer a unit
positive electric charge from an infinite distance to a given
point against an electric field
15b)
veiw some digrams here A metal rod can be made into a
magnet by divided touch me thod as shown in the diagram
above . The metal rod is stroke at the middle with
opposite pole end of two permanent magnets towards the
opposite ends several times opposite polarity are then
formed
15ci)
DRAW THE DIAGRAM
VR= 120 v ---- Vl = 50v -- --
Vc = 134 .39 v 22
==========COMPLETED==========