WAEC GCE 2018 Physics Answer Obj and Essay– Nov/Dece Expo

 WAEC GCE 2018 Physics (Obj & Essay) Answer - Nov/Dec Expo









Young modulus of a material or the modulus of



Potential Energy to kinetic Energy.



e = 0.7m

m=60 × 10^-3kg = 6.0×10^-2kg

K = 200Nm^-1

W = 1/2ke² = 1/2mv²

1/2ke² = 1/2mv²

V² = ke²/m = 200×0.7²/6.0×10^-2

V² = 98×10²/6

V² = 16.33×10²

V = √1633

V = 40.4

Speed = 40.4ms^-1



(i) Optical fibres have extremely high bandwidth

(ii) They have longer transmission distance

(iii) They have resistance to electromagnetic




It is used in geometric stations used to move a

satellite from low earth orbit into a

geostationary orbit.


Polar orbit satellite is used in earth mapping.



(i) Centripetal force

(ii) Centrifugal force


Ft = mDv

where F = force

t = time

Dv = change in velocity

m = mass of object

Hence F = mDv/t



(i) It can cause short and long term sun burn


(ii)It can cause blindness when flashed to the


(6b) Energy = hf

= 6.60×10^-34 × 4.82×10^14

= 3.18×10^-19J

= 1.99ev



V = 2πR/T

R = 9.6×10^6 + 6.4×10^6 =16×10^6 m

T = 24hrs =(24×60×60)s

V = 2×3.142×16×10^6/24×60×60

V = 1162.96m/s


8a) Mass is the amount of material contained in a body and the SI unit is Kg while Weight is the force exerted on a body by the gravity of the object. ..Mass is a scalar quantity( It has not specific direction), While Foce is a vector quantity (Its in the same direction with gravity)


Mass is measured in Kg

Weight is measured in Newton

Mass is a scalar quantity

Weight is a vector quantity

Mass is constant

Weight varies

8aii) Clockwise moment about the pivot.

Moment = Force x Distance

Moment = 250 x 0.75

Moment = 187.5Nm



Lenz’s law states that an induced current is in

such direction that it’s magnetic effect opposes

the change by which the current is induced.


(i) Magnets are used in construction of


(ii) They are used to store data in computers.

(iii) Used in magnetic resonance imaging



(a) Two coils: So as to produce an induced

current from one coil to the other.

(b) an iron core: To increase the strength of the

magnetic field.



Total resistance in series

Rt = R1 + R2

= 500 + 400

Rt = 900ohms

Taking E = 6v

E = V + ir

E = VR + Ir

E = I ( R + r)

I = E/R + r

taking r = 200ohms

I = 6/900+200

I = 6/1100

I = 0.005A

Hence the voltmeter reading

V = IR

= 0.005 × 200

= 1.09v



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