2018 Neco Physics Objective and Essay Questions and Answers | Neco Exam Expo

Physic-Obj
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17a)
i)Stay on top of large machinery operator training
ii)Keep large machinery clean, and maintain a clean environment
17bi)
-Compound Microsoft-
for viewing samples at high magnification (40 - 1000x), which is achieved by the combined effect of two sets of lenses: the ocular lens (in the eyepiece) and the objective lenses
17bii)
-Film projector-
an optical device that projects an image (or moving images) onto a surface, commonly a projection screen.
17c)
Artificial satellite orbits the earth and observes it. A rocket is designed to go to different planets, either taking people with it, or taking a space prob to take pictures of that planet.
17d)
data given
Rg=5n,Ig=10mA Vg=40V Rx=?
Ig=10mA =10*10^-3A
Ig=10^-2A
For Conversion Of galvanometer into voltmeter.
Vg=Ig(Rg+Rx)
Vg=Ig Rg + Ig Rx
Vg-Ig Rg =Ig Rx
Rx=Vg-IgRg/Ig
Rx=Vg/Ig-Rg
=40/10^-2 - 5/1
Rx=40/0.01 - 5/1
Rx=40-0.05/0.01
Rx=39.95/0.01
Rx=3995
the resistance of resistor is 3995
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15ai)
Force field is a region around a body in which it experiences an effect (force) due to the presence of another body
15aii)
i)gravitational field
ii)magnetic field
15b)
Show that the escape velocity(Ve) of an object from the earth surface is √2Gme/r
To prove the escape velocity (Ve) of an object from the earth surface we can say let the kinetic energy of the object of mass M is
Ek=1/2MVe^2
When an object is at any given point P which is at a distance X from the centre of the earth the force of unity between the object and earth is 
F=Gmm/X^2
Work done is taken the body against gravitational attraction DW=Fdx=Gmm/X^2 DX
Where W=work done in taking the body against gravitational attraction
W={R DW= {R Gmm/X^2 DM 
=Gmm {R X^2 DM = Gmm [X^2/Y {R
= -Gmm [1/X]R = - Gmm [1/~ - 1/R]
Or, W=Gmm/R
For the object to escape from the earth surface 
Ek=workdone,W
Ek=W
1/2MVe=Gmm/R
Ve=√2Gm/R(proved)
15ci)
i)Power supply smoothing applications
ii)RF coupling or filter capacitor applications
15cii)
Data given
d =4mm=4*10^-3 , 0.004m
A= 0.2m^2, V=300V
[Eo=8.85*10^-12fm^-1]
i)capacitance of the capacitor
using the approprate formula
C=EoAv/d
C=8.85*10^-12*0.2*200/0.004
C=8.85*10^-12*2*10^-1*2*10^2/4*10^3
C= 35.4*10^-11/4*10^-3
C= 8.85*10^-10^-11+3
C=8.85*10^-8F
the capacitance of the capacitor is 8.85*10^-8F
ii)Electric Field intensity between the plates
E=F/q =K.q.d/d^2/q
E=kQ/d^2 
E=8.85*10^-12*Q/d^2
but Q=CV
Q=8.85*10^-8*2*10^2
Q=17.7*10^-6 C,1.77*10^-7C
E=8.85*10^-12*1.77*10^-7/(4*10^-3)^2
E=15.7*10^-19/16*10^-6
E=1.57*10^-20/1.6*10^-5
E=0.98*10^-15
E=9.8*10^-1*10^-15
E=9.8*10^-16N|C or E=9.8*10^-16NC
the electric field intensity have theCT plates is 9.8*10^-16 NC
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(2a)

*In Tabular form*

(i)The velocity of streamline flow is less than critical velocity 
While
In turbulent motion the liquid moves with a velocity greater than the critical velocity of the liquid.

(ii)Streamline flow is laminar whereas, turbulent flow is
non-laminar.

(iii)
It is an orderly type of motion in which the liquid flows in parallel layers 

while, turbulent motion is disorderly type of motion.

(2aii)
Viscosity is the internal friction between layers of a liquid and gas in motion

Factors affecting viscosity

i)Temperature
ii)pressure

(2b)..........

(2c)
Conservative force are those forces which allows the opportunity of two way conversion among potential and kinetic energies are said to be conservative forces.

Example:
i)Gravitational force
ii)Magnetic force
ii)Electrostatic force

While 
Non - conservatve force is the force is called non conservative if work is done by the force is dependent on path followed by body .or The forces which are not conservative are called non conservative
forces.

Example:
i)Frictional forces
ii)Viscous forces
iii)Induction forces

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13a)
Specific heat capacity can be defined as the quantity of heat required to raise a unit mass of a material by one kelvin(k) or degrees Celsius('C)
13aii)
i)change in temperature of phase/State
ii)Change in resistance and in colour.
13aiii)
i)Linear expansivity results to expansion of metals or concrete bridges.
ii)It as well causes cracking of glass cup when hot water is poured into the glass cup.
13b)
i)Heat is nothing but the amount of energy in a body. As against this, temperature is something that measures the intensity of heat.
ii)Heat measures both kinetic and potential energy contained by molecules in an object. On the other hand, temperature measures average kinetic energy of molecules in substance.
iii)The main feature of heat is that it travels from hotter region to cooler region. Unlike temperature, which rises when heated and falls when cooled.
13ci)
when an inflated ballon is pierced and eleased, it obeys newton's third law of motion. Air rushes out from the pierced hole and the balloon moves in the opposite direction
13cii)
Jet
13d)
using MxCxD@ =MyCyD@y
Given D@x =D@y=(25-20)=5degree
Cx=1/2CY
then Mx[1/2CY]=MYCY
Mx/My=Cy/1/2Cy
Mx/My=2
Ratio of mass Of X to Y is 2:1

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6a).  The incident ray, reflected ray and normal at the point of incidence all lie on the same plane

6b i)  myopia can be corrected by placing a suitable concave or diverging lens in front of the eye

ii)  the action of the lens is to diverge the light rays entering the eye from a distant object and make them appear coming from the persons far Point

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