# Waec 2017 Physics Obj And Theory Expo Answer – 2017 May/June

Free WAEC Physics OBJ, theory/essay questions and answer for 2017 may/June expo

Verified Physics obj

21-30 CCBACBCBAB

41-50 BCDABCABCA

SECTION A ANS 5QUESTION

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1)

decrease in height (h)

increase in time (t)

this shows that distance changes with time

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3)

i)Brownian motion

ii)Atomic size

iii)Expansion

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2)

given that U=15m3^-1

R=U* sqr2h/g

h=20m

g=10

R=15*sqr2*20/10

R=15*sqr40/10

R=15*sqr4

R=15*2=30m

R=30m

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4)

L1=14cm F1=4N,F2=6N

L2=4cm, Lo=?

Using hooke’s law

4/14-Lo*6/4-Lo

4(4-Lo)=6(14-Lo)

16-4Lo=64-6Lo

-4Lo+6Lo=64-16

2Lo=48

Lo=48/2

Lo=24Cm

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5a)

i)force

ii)length

5b)

by increasing the density mosquitoes lavrva than the density of water

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6)

A)Energy efficient- so far the best light for interior lighting

B)Low production cost (of tubes, not of the ballasts)

C)Long life of tubes

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7)

i)It requires low voltage sources for it to function

ii)It cannot be easily broken

iii)It is cheaper and quite easy to manufacture

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8b)

If their distance and masses are doubled their corresponding force would also be doubled and the work done respectively

I.e.Workdone=Force * distance

Force= Mass * Acceleration

W= Mg * d

|

Increase

8c)

-Acceleration due to gravity

– At maximum height, final velocity is zero

8d)

i)pushing someone on a swing.

ii)Tuning a radio to a particular frequency.

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10a)

A wave front is an imaginary surface passing through the points of a medium oscillatory in phase

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SECTION B ANS 3 QUESION

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12ai)

Nuclear fission is a nuclear reaction in which a heavy nucleus splits spontaneously or on impact with another particle, with the release of energy.

12aii)

A graphite reactor is a nuclear reactor that uses carbon as a neutron moderator, which allows un-enriched uranium to be used as nuclear fuel.

12aiii)

Boron rods are used in

nuclear reactors to control the fission rate of uranium and plutonium. They are composed of chemical elements such as boron, silver, indium and cadmium that are capable of absorbing many neutrons without themselves fissioning.

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