A sound pulse sent vertically downwards into the earth is reflected from two different layers of the earth such that echoes are heard 1.2s and 1.4s. Assuming speed of the pulse is 2000ms-1, calculate the distance between the layers.
A200 m
B400 m
C2400 m
D2600 m
E2800 m
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Question 2042
waec1989
Which of the following is a stringed instrument?
Aflute
Btrumpet
Cpiano
Ddrum
Esaxophone
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Question 2043
waec1989
The distance between a node and an anti-node for a transverse wave is equal to
Athe wavelength
Bthrice the wavelength
Cone-half of the wavelength
Done-quater of the wavelength
Ethree quaters of the wavelength
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Question 2044
waec1989
The refractive index of a given transparent medium is 1.4. Which of the following is the minimum internal angle for total internal reflection to take place in the medium?
A30o
B36o
C44o
D46o
E54o
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Question 2045
waec1989
The image in a pine-hole camera is always
Adiminished
Benlarged
Cupright
Dinverted
Eblurred
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Question 2046
waec1989
A ray of light is incidence on a plane mirror at an angle of 35o. What is the angle by the reflected ray with the surface of the mirror?
A125o
B70o
C65o
D55o
E35o
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Question 2047
waec1989
A short chain is usual attached to the back of a petrol tanker trailing behind it to ensure that the
Apetrol tanker is balanced on the wh eel
Bheat generated by friction in the engine can be conducted to the floor
Ccharges generated by friction in the tanker can be conducted to the earth
Dthe tanker moves slowly as the chain touches the floor
Echain produces sound for the resonance of the tanker engine
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Question 2048
waec1989
Which of the following instruments can be used to compare the relative magnitudes of charges on two given bodies?
AThe electrophorous
BEbonite rod
CProof plane
DGold leaf electroscope
ECapacitor
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Question 2049
waec1989
All the heat generated by a current of 2A passing through a resistor of 6Ω for 25s is used to evaporate 5 g of a liquid at its boiling point. What is the specific latent heat of the liquid?
A60 Jg-1
B120 Jg-1
C300 Jg-1
D360 Jg-1
E1500 Jg-1
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Question 2050
waec1989
A block of ice at its melting point is left on a table in the atmosphere and observed to melt gradually. Which of the following statements is true about the melting process?
Athe reaction force of the table on the ice breaks the ice into water molecules
Bheat extracted from the ice block makes the ice block cold
Cthe ice block absorbs heat from the atmosphere and its temperature rises
Dthe atmosphere absorbs heat from the ice block and its temperature falls
Ethe ice block absorbs heat from the atmosphere and its temperature remains constant as it melts
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Question 2051
waec1989
Calculate the heat energy required to vapourize 50g of water initially at 80oC if the specific heat capacity of water is 4.2Jg-1K (specific latent heat of vapourization of water is 2260Jg-1).
A533000J
B230000J
C117200J
D113000J
E4200J
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Question 2052
waec1989
Which of the following substance is not a good conductor of electricity?
AHuman body
BGlass
CAluminium
DEarth
ECopper
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Question 2053
waec1989
Water in an open container boils at a lower temperature when heated at the top of a mountain than at sea-level because at the top of a mountain the
Arelative humidity is higher than at sea-level
Brays of the sun adds more heat to the water
Ctemperature is lower than that at sea-level
Dpressure is lower than that at sea-level
Epressure is more than that at sea-level
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Question 2054
waec1989
Which of the following statements is/are not correct?
AEvaporation takes place only at the surface of the liquid
BBoiling takes place throughout the volume of the liquid
CEvaportaion takes place at all temperatures
DBoiling takes place at a particular temperature for a liquid at a fixed external pressure
EThe boiling point of a liquid is not affected by impurities
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Question 2055
waec1989
Which of the following surfaces will radiate heat energy best?
ARed
BWhite
CBlack
DYellow
EBlue
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Question 2056
waec1989
A thermometer has its stem marked in millimeter instead of degree Celsius. The lower fixed point is 30mm and the upper is 180mm. Calculate the temperature in degree celsius when the thermometer reads 45mm.
A67.5oC
B30.0oC
C25.0oC
D15.0oC
E10.0oC
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Question 2057
waec1989
An engine raises 1000kg of water through a height of 60m in 20s. What is the power of the engine? (Take g = 10ms-2>).
A120,000 W
B30,000 W
C333 W
D300 W
E30 W
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Question 2058
waec1989
Which of the following is a derived unit?
AMetre
BCoulomb
CKilogram
DSecond
EAmpere
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Question 2059
waec1989
The motion of the prongs of the sounding tuning fork is
Arandom
Btranslational
Crotational
Dvibratory
Evibratory and rotational
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Question 2060
waec1989
A stone tied to a string is made to revolve in a horizontal circle of radius 4m with an angular speed of 2 rad per sec. With what tangential velocity will the stone move off the circle if the string is cut?
