%100 VERIFIED 2016 NECO PHYSICS OBJ AND ESSAY ANSWERS

Physics OBJ
1-10 BABDAECDEB
11-20 CDADDDBCBB
21-30 DBEBBEACEB
31-40 EBEBCBCCDA
41-50 BDBCEDAAAE
51-60 AAABBACECA

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.

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2i) total distance = 5m+10m

=15m

2ii) magnitude of his .=

D=sqrt: 5² + 10²

D= sqrt: 25+100

D=sqrt: 125

D= 11.18

2a)

i)distance covered=5m+10m=15m

ii)magnitude of his displacement

=a^2=b^2+c^2

x^2=5^2+10^2=25+100

x^2=125

x=sqr125

=5sqr5m

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

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4a - the wheel and axle

-the inclined plane

-the wedge

-the pulley

-the screw (use 2)

4b loading

5)

V1=700cm^3, T1=30dgree-census

+273=303k, P1=606mmHg

V2=700-300=400cm^3, T2=47+273=320k

from general gas law

P1V1/T1 = P2V2/T2

606*700/303=P2*400/320

P2=606*700*320/303*400

P2=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).

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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^-5c r=30cm

30/100=0.3m

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=450kv

9b)Energy stored in a capacitor

E= ½cv²

=½×4×800²

=2×640000

=1280000J

Therefore energy stored = 1280KJ or 1.2MJ

(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.

(13a) Dew point is the temperature at which

the water present in the air is just sufficient

to saturate it

(13b)mist is form when the air near the

surface of the land cools until it reaches dew

point,water vapour originally present in the

air begins to condense around tiny

suspended dust particles in the air.

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

12) CLICK HERE TO VIEW NO.12 IMAGE
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=40r3
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 workdone in driving
a unit
charge of electric current from one point to
another
in a closed circuit. It is measured in volta(V)
15b)
CLICK HERE TO VIEW NO.15b IMAGE
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)
CLICK HERE TO VIEW NO.15ci IMAGE
VR=120v---->Vl=50v---->Vc=134.39v
220v,506z

15cii)
V^2=Vr^2+(Vl-Vc)^2
220^2=120^2+(50-Vc)^2
48400=14400+(50-Vc)^2
48400=14400=(50-Vc)^2
34000=(50-Vc)^2
50-Vc=sqr34000
50-Vc=184.39
-Vc=184.39-50
Vc=134.39v
;the potential difference acrross the capaitor
is
134.39v