The density of water is 1g\(cm^3\) while that of ice is 0.9\(cm^3\), calculate the volume change when 90g of ice is completely melted
A0\(cm^3\)
B9\(cm^3\)
C10\(cm^3\)
D90\(cm^3\)
E100\(cm^3\)
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Question 2
waec1994
The density of a body is \(5\times10^3kgm{^-3}\) and it weighs 1N in air. Calculate the apparent weight of the body when totally immersed in water. (Density of water =\(10^3kgm{-3}, g= 10ms^{-2}
A0.02N
B0.08N
C0.20N
D0.80N
E1N
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Question 3
waec1994
A light wave travels from air into a medium of refractive index 1.54. If the wavelength of the light in air is \(5.9\times10^{-7}\)m, calculate its wavelength in the medium
A\(2.5\times10^{-7}\)m
B\(3.8\times10^{-7}\)m
C\(4.6\times10^{-7}\)m
D\(5.2\times10^{-7}\)m
E\(6.1\times10^{-7}\)m
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Question 4
waec1994
Calculate the time taken to heat 2kg of water from 50°C to 100°C in an electric kettle taking 5A, from a 210V supply. (Specific heat capacity of water = 4200\(kg^{-1}K{-1}\)
A2.5 minutes
B5.7 minutes
C6.7 minutes
D7.5 minutes
E9.5 minutes
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Question 5
waec1994
The pressure of air in a tire is \(22.5Nm^{-2}\) at 27°C. If the air in the tyre heats up to 47°C, calculate the new pressure of the air, assuming that no air leaks out and that the change in volume of the air can be neglected.
A\(21.10Nm^{-2}\)
B\(24Nm^{-2}\)
C\(39.07Nm^{-2}\)
D\(45Nm^{-2}\)
E\(97.25Nm^{-2}\)
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Question 6
waec1994
\(500cm^{-3}\) of a gas is collected at 0°C and at a pressure of 72cm of mercury. What is the volume of the the gas at the same temperature and at a pressure of 76cm of the same mercury?
A\(\frac{76\times500}{72}cm^3\)
B\(\frac{72\times500}{76}cm^3\)
C\(\frac{72\times76}{500}cm^3\)
D\(\frac{76}{72\times500}cm^3\)
E\(\frac{72}{76\times500}cm^3\)
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Question 7
waec1994
An electric kettle rated 1500W boils away 0.3kg of a liquid at its boiling point every 300s. Calculate the specific latent heat of the vaporisation of the liquid
A1.5 x \(10^6Jkg^-1\)
B1.35 x \(10^6Jkg^-1\)
C1.5 x \(10^5Jkg^-1\)
D4.5 x \(10^2Jkg^-1\)
E3 x \(10^2Jkg^-1\)
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Question 8
waec1994
500g of water is heated so that its temperature rises from 30°C to 72°C in 7 minutes. calculate the supplied per minute. (Specific heat capacity of water is 4200J\(kg^{-1}K^{-1}\)
A9000J
B12600J
C21000J
D25200J
E88200J
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Question 9
waec1994
A metal rod of length 40cm at 20°C is heated to a temperature of 45°C. If the new length of the rod is 40.05cm. Calculate its linear expansitivity
A1.2 x \(10^{-5}K{-1}\)
B2.5x \(10^{-5}K{-1}\)
C3.5x \(10^{-5}K{-1}\)
D4.5x \(10^{-5}K{-1}\)
E5x \(10^{-5}K{-1}\)
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Question 10
waec1994
A body accelerates uniformly from rest at \(2ms^{-2}\). Calculate the velocity after traveling 9m
A36\(ms^{-1}\)
B18\(ms^{-1}\)
C6\(ms^{-1}\)
D4.5\(ms^{-1}\)
E4.24\(ms^{-1}\)
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Question 11
waec1994
A ball is dropped from a height of 45m above the ground. Calculate the velocity of the ball just before it strikes the ground. (Neglect air resistance and take g as \(10ms^{-2}\)
A21.2\(ms^{-1}\)
B30\(ms^{-1}\)
C300\(ms^{-1}\)
D450\(ms^{-1}\)
E900\(ms^{-1}\)
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Question 12
waec1994
A cell of e.m.f. 1.5V and internal resistance of 2.5Ω is connected in series with an ammeter of resistance 0.5W and a resistor of resistance of 7.0Ω. Calculate the current in the circuit.
A0.15A
B0.20A
C2.10A
D3A
E6.6A
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Question 13
waec1994
A note of frequency of 2000Hz has a velocity of \(400ms^{-1}\). What is the wavelength of the note?
A800m
B200m
C5m
D2m
E0.2m
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Question 14
waec1994
The wave function of a metal is 8.0 x \(10^{-19}\)J. Calculate the wavelength of its threshold frequency. (Speed of light in a vacuum = 3 x \(10^8ms^{-1}, Planck's constant = 6.6 \times 10^{-34}\)Js)
A0.8 x \(10^{-7}\)m
B1 x \(10^{-7}\)m
C2.3 x \(10^{-7}\)m
D3.8 x \(10^{-7}\)m
E12.4 x \(10^{-7}\)m
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Question 15
waec1994
The nucleon number and the proton number of a neutral atom of an element are 238 and 92 respectively. What is the number of neutrons in the atom?
A330
B238
C146
D119
E73
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Question 16
waec1994
In 24 days a radioactive isotope decreases in mass from 64g to 2g. What is the half life of the radioactive material
A0.75 days
B2.58 days
C4 days
D4.80 days
E6 days
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Question 17
waec1994
When an atom loses or gains a charge, it becomes an
Aion
Ban electron
Ca neutron
Da proton
Ea deuteron
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Question 18
waec1994
Which of the following substances is not an insulator?
AAluminium
BGlass
CPlastic
DClay
ECork
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Question 19
waec1994
Beta particles are
Aelectrons
Bprotons
Cneutrons
Dhelium nuclei
Etritium nuclei
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Question 20
waec1994
A transformer with 5500 turns in its primary winding is used between a 240V a.c supply and 120V kettle. Calculate the number of turns in the secondary winding
