2018/19 PRIVATE WASSCE ( WAEC GCE ) PHYSICS QUESTIONS AND ANSWERS

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*WAEC GCE 2018: CONFIRMED PHYSICS ESSAY SOLUTIONS BY COOLBOY.*

*Blastexams.blogspot.com_*

(1a)

Young modulus of a material or the modulus of

elasticity.

(1b)

Potential Energy to kinetic Energy.

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

(2)

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

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(3)

(i) Optical fibres have extremely high bandwidth

(ii) They have longer transmission distance

(iii) They have resistance to electromagnetic

interference

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(4a)

It is used in geometric stations used to move a

satellite from low earth orbit into a

geostationary orbit.

(4b)

Polar orbit satellite is used in earth mapping.

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(5a)

(i) Centripetal force

(ii) Centrifugal force

(5b)

Ft = mDv

where F = force

t = time

Dv = change in velocity

m = mass of object

Hence F = mDv/t

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

(6a)

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

effects.

(ii)It can cause blindness when flashed to the

eyes.

(6b) Energy = hf

= 6.60×10^-34 × 4.82×10^14

= 3.18×10^-19J

= 1.99ev

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

(7)

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)

8ai)

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

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(11a)

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.

(11b)

(i) Magnets are used in construction of

speakers.

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

(iii) Used in magnetic resonance imaging

machines.

(11ci)

(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.

(11cii)

(11d)

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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