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Physics (Essay & Objective) Neco 2017 Free Expo Answers




Physics (Essay & Objective) Neco 2017 Free Expo Answers
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Monday 10th July 2017
OBJ & Essay – Physics – 2:30pm – 5pm
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*VERIFIED-PHYSICS-OBJ*

1-10:CEABCBAABB
11-20:DCCBCBCCAE
21-30:BECDDBEDDE
31-40:DBAEADBABA
41-50:CBDCBBBDCB
51-60:CEDDCBAEAA



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(1a)
(i)Propellant
(ii)Nozzle

(1aii)
(i)It is used for communication
(ii)It is used to access geographical dispersed terrains and even topography that characterise the nation's landscape

(1b)
Given:
Object distance for eyepiece=3.0cm
Final image distance V =?
Focal length of eyepiece f=5.0cm
Using mirror / lens formular

1/f = 1/u + 1/v
1/5= 1/3 + 1/v
Multiplying through with 15v
3v = 5v + 15
3v - 5v = 15
-2v = 15
V = - 15/2
V= - 7.5cm

The final image is virtual and 7.5cm from the eyepiece on the same side of the eyepiece as the object

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(4a)
The specific latent heat of vaporization of a substance is the quantity of heat required to change a unit mass of the substance from liquid to vapour without change of temperature

(4b)
Kinetic energy is that possessed by a body due to its motion. While potential energy is that possessed by a body due to its height or state

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(5a)
(i) solar
(ii) wind

(5b)
Given:
M1=15kg, U1 =10m/s , V =?
M2 = 5kg, U2 =0 m/s

Using
M1V1 + M2V2 = V(M1 + M2)
15(10) + 5(0) V(15 + 5)
150 = 20V
==>20V = 150
V = 150 / 20
V= 7. 5m/s
Common velocity =7.5m/s

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(9a)
(i) Over charging(for secondary cell)
(ii) self discharge (for primary cell)

(9b)
Self discharge: A primary cell lose a considerable percentage of their charge when stored at room temperature. This is due to non-current producing "side" chemical reaction that occur within the cell even when no load is applied

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(10)
(i)Fusion is more easily achieved with lightest elements such as hydrogen
(ii) The raw materials required for fusion are more cheaply and readily available
(iii) Fusion process produce less dangerous by-products

12ai) Newton's second law of motion states that the rate of change of momentum is proportional to the impressed fotvr and takes place in the direction of the force

12aii)- The motion of the strings in a musical instrument eg. Guitar
- The motion of the balance wheel of a watch

12bi) Resultant force is that single force which acting alone will have the same effect in magnitude and direction as two or more forces acting together

12bii) Equilbrum force is that single force which will balance all the other forces taken together. It is equal in magnitude buy opposite in direction to the resultant force

12ci)
Resultant,Force,F=sqr4^2+3^2
F=sqr16+9
Fsqr25=5N
12cii)
using F=m(v-u)/t
5=5.5(v-2)/(5*60)
5*60*5=5.5(v-2)
=5.5(v-2)=1500
V-2=272.7
V=272.7+2
V=274.7m|s
final velocity of body = 274.7m|s


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13ai)- Solar energy is for providing a cheap and clean source of hot water supply.
- Solar energy provides electricity supply

13aii)-Renewable energy are those that can be replaced as they are used up. They can be continually replenished as they are exploited and utilized while Non-Renewable energy are those that cannot be replenished as they are used up
-Examples of renewable energy are Solar energy, wind energy, Biomass and Bio feuls while examples of Non renewable energy are Coal and wood, Fossil fuel, Petroleum and Natural gas, Nuclear energy

13b) The principle of conservation of linear momentum us also utilized in the propulsion of jet aircraft. Gases are burnt within the combustion chambers of the engine. As jets of hot gases are expelled downwards through the tail nozzle at very high speeds from the aircraft, an equal and opposite momentum is given to the rocket or aircraft which then moves

13c)




*15a)*
Coulomb's law state that magnitude of the electrostatic force of attraction between two point charges is directly proportional to the product of the magnitudes of the charges and inversely proportional to the square of the distance between them

*15bi)*
Diagram(will sent as image)

*15bii)*
Let equivalent resistance be R
1/R = 1/R1 + 1/R2 + 1/R3
I/R = R2R3 + R1R3 + R1R2 / R1R2R3
R= R1R2R3 / R1R2+R2R3+R1R3

*15c)*

GIVEN!
200Ω C =4mf f=50h2 π =3.14
Impedance Z =√R^2 + (1/2Ω + c) ^2
Z =√200^2 + (1/2×3.145×50×4×10^-6)^2
Z=√200^2 + 796.178^2
Z=√40000 + 633900
Z=√673900
Z=821Ω


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