If the leaves a positively charged electroscope collapse completely as an object is brought near the cap of the electroscope, the objects possesses
Aan equal amount of positive charge
Bless amount of negative charge
Cno charge
Da positive charge
Ean equal amount of negative charge
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Question 12
waec1988
A sounding tuning fork is brought near the end of a pipe containing an air column and the loudness of the sound increases. This effect is due to
Adiffraction
Ban echo
Cresonance
Dinterference
Ereverberation
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Question 13
waec1988
A boy standing a distance from the foot of a tall cliff claps his hands and hears an echo 0.5s later. If the speed of sound is 340ms1, how far is he from the cliff?
A17m
B34m
C85m
D170m
E680m
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Question 14
waec1988
Which of the following statement s is/are not correct about a standing wave? I. It is formed by the superimposition of two progressive waves traveling in the same direction II. All points on the wave are vibrating with maximum displacement III. It is formed by the superimposition of two progressive waves of different amplitudes traveling in opposite directions
AI only
BII only
CI and II only
DII and III only
EI,II and III
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Question 15
waec1988
A source of sounds produces waves in air of wavelength1.65m. If the speed of sound in air is 330ms-1 the period of vibration in seconds is
A200
B2.0
C0.5
D0.02
E0.005
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Question 16
waec1988
The change of the direction of a wave-front because of a change in the velocity of the wave in another medium is called?
Arefraction
Breflection
Cdiffraction
Dinterference
Edispersion
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Question 17
waec1988
The ability of the eye to focus objects at different distances is called
Apower
Baccommodation
Cnormal vision
Dpersistence of vision
Elong sight
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Question 18
waec1988
An object is placed 36cm from a converging lens of focal length 24cm.If a real image which is 4cm high is formed, Calculate the height of the object.
A2.0cm
B4.0cm
C6.0cm
D8.0cm
E10.0cm
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Question 19
waec1988
The velocities of light in air and glass are 3.0 x10\(^8\)ms\(^{-1}\) and 1.8 \(\times \)10\(^8\) ms\(^{-1}\) respectively. Calculate the sine of the angle of incidence that will produce an angle of refraction of 30° for a ray of light incident on glass.
A1.2
B1.0
C0.8
D0.6
E0.3
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Question 20
waec1988
A transparent rectangular block 5.0cm thick is placed on a black dot. The dot when viewed from above is seem 3.0cm from the top of the block calculate the refractive index of the material of the block.
A2/5
B3/5
C3/2
D5/3
E5/2
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Question 21
waec1988
Which of the following statements is/are not correct about image formed by a plane mirror?
I. The magnification produced is 1
II. The image distance is same as the object distance
III. The image is real
IV. The image is laterally inverted
AI only
BII only
CIII only
DI & II only
EII & IV only
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Question 22
waec1988
Which of the following will affect the saturation vapour pressure of a liquid?
ATemperature of the liquid
BHumidity of air
CVolume of vapour
DVolume of the liquid
Emass of the liquid
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Question 23
waec1988
Which of the following instrument may be used to measure the relative humidity?
AHydrometer
BBarometer
CManometer
DHypsometer
EHygrometer
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Question 24
waec1988
The temperature at which the water vapour present in the air is just sufficient to saturate it is called the
Aice point
Bboiling point
Csteam point
Ddew point
Esaturation point
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Question 25
waec1988
0.5kg of water at 10oC is completely converted to ice by extracting 188000J of heat from it. If the specific heat capacity of water is 4200J kg-1C-1, calculate the specific latent heat of fusion of ice.
A9.0 KJ kg-1
B84.0 KJ kg-1
C168.0 KJ kg-1
D334.0 KJ kg-1
E336.0 KJ kg-1
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Question 26
waec1988
Which of the following statements about radiant heat is/are not correct?
I. radiant heat cannot travel through a vacuum
II. rough surfaces emit radiant heat more than polished surfaces
III. Dark surfaces absorb radiant heat more than bright surfaces
AI only
BII only
CIII only
DI & II only
EII & III only
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Question 27
waec1988
Which of the following best explains a person suffers more severe burns when his skin is exposed to steam than when boiling water is poured onto his skin?
Asteam is at a higher temperature than boiling water
Bsteam posses greater heat energy per unit-mass than boiling water
Csteam spreads more easily over a wider area of the skin than boiling water
Dsteam panetrates more easily over a wider area of the skin than boiling water
Ethe specific latent heat of vaporization is released in changing from boiling water to steam
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Question 28
waec1988
In which of the following is the expansion of solids a disadvantage?
Athe fitting of wheels in rims
Bfire alarms
Cthe thermostat
Dthe bimatellic thermometer
Ethe balance wheel of a watch
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Question 29
waec1988
Which of the following is a reason why a concrete floor feels colder to the bare feet than a mat on the same floor during the rainy season?
AA mat if s better conductor of heat than the feet
BMat losses heat to the bare feet at a faster rate than concrete floor
CMat losses heat to the bare feet while the concrete floor extracts heat from them
DConcrete floor is a better conductor of heat than the mat
EMat is a better conductor of heat than the floor
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Question 30
waec1988
A given mass of gas has a pressure of 80Nm-2 at a temperature of 47oC. If the temperature is reduced to 27oC with the volume remaining constant, the new pressure is
