The odor of a leaking gas is perceived at a distance from the source. This is made possible by the process of
ASublimation
BDiffusion
COsmosis
DEvaporation
ECapillarity
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Question 12
waec1997
The half-life of a radioactive material is 6hrs. What quantity of 1kg of the material would decay in 24 hours?
A\(\frac{15}{16}\)kg
B\(\frac{1}{2}\)kg
C\(\frac{1}{4}\)kg
D\(\frac{1}{8}\)kg
E\(\frac{1}{6}\)kg
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Question 13
waec1997
When a paint brush is removed from clean water, the bristles of the brush are pulled together because of
AThe viscosity of the surrounding air
BThe low density of water
CSurface tension forces
DThe weight of the brush bristles
EThe mass of the brush bristles
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Question 14
waec1997
Which of the following statements is not true of nuclear fission?
AMother nucleus is broken into two daughter nuclei of roughly equal parts
BNeutron is normally used in bombarding heavy nucleus
CTwo light nuclei are made to combine to form a heavy nucleus
DVery enormous energy is released
EThere is an apparent loss of mass
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Question 15
waec1997
The ratio of tensile stress to tensile strain is known as
AModulus of integrity
BModulus of elasticity
CShear modulus
DBulk modulus
EYoung’s modulus
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Question 16
waec1997
Which of the following is not correct about the Rutherford’s model of an atom?
AThe mass of an atom is concentrated around the nucleus
BThe nucleus of an atom is positively charged
CThe nucleus is surrounded by the electron cloud
DThe model is applicable to atoms with only one electron in the outer shell
EThe diameter of the nucleus is \(10^{-15}m\)
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Question 17
waec1997
Which of the following statements about kinetic theory of matter is not correct?
AThe molecules of matter are always in motion
BWhen a body is heated the average kinetic energy of its molecules decreases
CMolecules of a liquid move more freely than those of a solid
DMatter is made up of very tiny particles called molecules
EThe molecules of a gas move more freely than those of a liquid
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Question 18
waec1997
What is the frequency of a radio wave of wavelength 150m if the velocity of radio waves in free space is 3 x \(10^8ms^{-1}\)?
A4.5 x \(10^{10}\)Hz
B5x \(10^{9}Hz\)
C4.5 x \(10^{8}Hz\)
D2 x \(10^{7}Hz\)
E2 x \(10^{6}Hz\)
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Question 19
waec1997
A cup containing 100g of pure water at 20°C is placed in a refrigerator. If the refrigerator extracts heat at a rate of 840J per minute, calculate the time taken for the water to freeze. Neglect the heat capacity of the material of the cup. (Specific heat capacity of water =4.2J\(g^{-1}K^{-2}\))((Specific latent heat fusion of water =336J\(g^{-1}\)
A15minutes
B20 minutes
C42 minutes
D50 minutes
E84 minutes
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Question 20
waec1997
A converging lens of focal length 15cm is used to obtain a real image magnified \(1\frac{1}{2}\) times. Calculate the distance of the image from the lens?
A37.5cm
B22.5cm
C15cm
D7.5cm
E3.3cm
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Question 21
waec1997
A fixed mass of gas occupies a volume of 20\(cm^3\) at a fixed pressure of 700mmHg. Assuming that the temperature remains constant, what will be the volume of the gas at 750mmHg?
A2.5\(cm^3\)
B15.5\(cm^3\)
C18.7\(cm^3\)
D21.4\(cm^3\)
E72.5\(cm^3\)
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Question 22
waec1997
Calculate the quantity of heat released when 100g of steam at 100°C condenses to water(Take the specific latent heat of vaporization of water as 2.3x \(10^6Jkg^{-1}\))
A2.3x\(10^{1}J\)
B2.3x\(10^{2}J\)
C2.3x\(10^{4}J\)
D2.3x\(10^{5}J\)
E3.3x\(10^{7}J\)
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Question 23
waec1997
A solid material of volume 100\(cm^{-3}\) is heated through a temperature difference of 40°C. Calculate the increase in the volume of the material if its linear expansitivity is 2 x \(10^{-6}K{-1}\)
A2.4 x\(10^{-2}cm^{-3}\)
B1.6 x\(10^{-2}cm^{-3}\)
C8 x\(10^{-2}cm^{-3}\)
D5 x\(10^{-2}cm^{-3}\)
E4 x\(10^{-2}cm^{-3}\)
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Question 24
waec1997
Whenever light waves are restricted to a specific plane they are said to be
ADiffracted
BRefracted
CDiffused
DRegularly reflected
EPlane polarized
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Question 25
waec1997
At what distance from a simple microscope must an object be placed so that the image 5 times the size of the object is produced 20cm from the lens?
A2cm
B3.3cm
C4cm
D5cm
E15cm
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Question 26
waec1997
When white light is incident on a glass prism the spectrum produced on a screen placed beyond the prism is due to?
ADiffraction
BReflection
CRefraction
DPolarisation
EInterference
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Question 27
waec1997
Which of the following explains why a thick glass cup cracks when boiling water is poured into it?
AUnequal expansion of the exterior and interior walls of the cup
BAnomalous expansion of the water
CGreater specific latent capacity of water compared with that of glass
DLarge increase in the heat capacity of the cup
EHigh density of the water
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Question 28
waec1997
Steel bars each of length 3m at 28°C are to be used for constructing a rail line. If the linear expansitivity of the steel is 1 x \(10^{-5}K^{-1}\),what is the safety gap that must be left between the successive bars if the highest temperature expected is 40°C?
A1.2x \(10^{-1}cm\)
B7.2x\(10^{-1}cm\)
C6x\(10^{-1}cm\)
D3.6x\(10^{-2}cm\)
E1.8x\(10^{-1}cm\)
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Question 29
waec1997
A piece of copper of mass 30g loses 60J of heat energy. If the specific heat capacity of copper is 400J\(kg^{-1}K^{-1}\), Calculate the change in the temperature of the copper
A0.2K
B0.8K
C2K
D4.5K
E5K
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Question 30
waec1997
A solid plastic cube of side 0.2m is submerged in a liquid density of 0.8kg\(m^{-3}\). Calculate the upthrust of the liquid on the cube (g=10\(ms^{-2}\)
