# NECO GCE Physics obj & Theory Questions And Answers For 2018

NECO GCE Physics obj & Theory Questions And Answers For 2018

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Physics OBJ:
1-10: ACEBBECBED
31-40: BEDBACDEED

Completed

Physics Theory:
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(1a)
An Artificial Satellite is an artificial object that is
manufactured by humans and launched into the Earth’s orbit
or in another planet’s orbit. These satellites revolve round
the planets and provide all the information about the planet
through satellite imagery.

(1b)
Rocket is multistage because the effectiveness of a rocket
is inversely proportional to its mass and using stages
allows us to reduce the mass of the rockets as it operates.

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(3a)
Amplitude of a simple harmonic motion is defined as the
maximum distance that an object moves from its equilibrium
position.

(3b)
Tabulate:
Speed:
(i) Speed is how fast an object is moving.
(ii) It is calculated by the displacement of space per a
unit of time.
(iii) speed does not deals on direction
Velocity:
(i) Velocity is the rate at which an object changes position
in a certain direction.
(ii) It is calculated by the displacement of space per a
unit of time in a certain direction.
(iii) Velocity deals with direction

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(5a)
Heat Capacity (Cp) of a body is the quantity of heat
required to raise the temperature of the body by 1 Kelvin.

(5b)
m=5kg, I=3.3610^5Jkg^-1
H=5
3.3610^5J
H=16.8
10^5J

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(6a)
The reason why convex mirror is used as a driving mirror is because they give erect image of an object.

(6b)
V = 0.4ms^-1
f = 6Hz
Apply
V = fΔ
Δ = v/f
=0.4/6 = 0.67m

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(8a)
(i) It is the measure of how easily an electron can flow in that given wire.
(ii) It depends on experiment temperature, electron density, current density .

(8b)
E= 12v
R= 1.2 Ω
r= 4 Ω
I= ?

E= I(R+r)
I= E/R+r
I= 12/1.2+4
I= 12/5.2
:. I= 2.31A

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(10a)
Surface tension is the force acting along the surface of a
liquid causing the liquid surface to balance like a
stretched elastic slain.

(10b)
In a tabular form:
(i) Molecules of water
(ii) Force of attraction between molecules of different
kind.
Cohesion
(i) Molecules of glass and water
(ii) Force of attraction between molecules of same kind.

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(12a)
Friction is the force that comes to play a role in between
the surfaces of the two solids in contact and tends to
oppose the motion of one over the other.

(12bi)
A projectile is an object or body launched into the air and
allowed to move on its own or more freely under gravity.

(12bii)
(i) A thrown javelin.
(ii) Shooting of catapult.

(12c)
Centrifugal takes place along the radius of the circle from
the center out towards the object while centripetal, it is
the opposite, taking place also along the radius of the
circle, but from the object in towards the center.

(12d)
From 1st condition of equilibrium;
Total upward forces = Total downward forces.
C+D = 20N
From 2nd condition.
Total clockwise moment = Total anticlockwise moment
205 = D(12+5) = 17D
100 = 17D
D = 100/17
D = 5.88N
From 1st condition of equilibrium
C+D = 20N
C + 5.88 = 20
C = 20 – 5.88
C = 14.12N

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(13a)
(i) By contact
(ii) By friction

(13aii)
Uncharged body is placed on an insulator then a charged body is brought near it without contact, then the finger is used to touch the uncharged body momentarily then removed, it will found that uncharged body is having opposite charged of the charged body.

(13b)
Elastic iron regulates it’s temperature by means of its thermostat which consists of bimetallic, when the heating element supply heat, the bimetallic begins to bend away from the contact of the power supply and when the heat supply is enough to bend it away the power supply cut-off and when it also cool enough the bimetallic again makes contact and the supply returns.

(13ci)
Boyle’s law states that at constant temperature for a fixed mass, the absolute pressure and the volume of a gas are inversely proportional.
PV = k(constant)

(13cii)
Using Boyle’s law
P1V1=P2V2

Where P1 = 760
P2 = ?
V1 = 3
V2 = Half of the Initial Volume = 1.5

Finding P2,
P2 = P1V1/V2
= 760 x 3 / 1.5
= 2280/1.5
= 1520mmHg

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(14a)
Compression is the ability of wave to compress/sink together after propagation WHILE refraction is the ability of wave to depart after propagation.

(14b)
(ii) Operation of the pin-hole camera.

(14ci)
(i) Echo is used in the determination of the speed of sound in air
(ii) It is used in exploration for gas and oil

(14cii)
(i) Lenses are used to correct defects in human eyes
(ii) They are used in the compound microscope

(14di)
Vibrations of the air in an open pipe produces echo while that in a plucked stretched string produces interference

(14dii)
fo = 220Hz
f1 = 2fo = 3fo
For the open pipe
f1 = v/l
=2*220 = 330/l
L = 330/440 = 0.75
Length of the given pipe
=0.75m or 75cm

For the closed pipe
f1 = 3v/4l
3220 = 3330/4l
660 = 990/4l
4l = 990/660
4l = 1.5
L = 1.5/4 = 0.375m
Length of the closed pipe
=0.375m or 37.5cm

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