The image of an object formed by a convex mirror is
Areal, errect and enlarged
Breal, inverted and enlarged
Cvirtual, erect and diminished
Dvirtual, erect and enlarge
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Question 13
waec2008
The distance between a concave mirror and an object placed in front of it is 1.0m. If the raduis of curvature of the mirror is 4.0m, the image formed will be
A2.00m behind the mirror
B2.00m in front of the mirror
C1.25m in front of the mirror
D1.25m behind the mirror
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Question 14
waec2008
In the day time, it is possible to see under shady areas such as under a tree because light has undergone
Ainternal reflection
Brefraction
Cdiffraction
Ddiffuse reflection
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Question 15
waec2008
Light is considered as a transverse wave because it travels
Athrough material without causing disturbance of the medium
Bthrough space with constant speed
Cin a direction parallel to the plane containing the electric and magnetic fields
Din a direction perpendicular to the plane containing the electric and magnetic fields
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Question 16
waec2008
It takes a shorter time for a liquid to boil at the top of a mountain than at the base because at the top, the
Atemperature is higher
Bpressure is lower
Chumidity is higher
Dtemperature is constant
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Question 17
waec2008
The working principle of a pressure cooker is based on the
Aincrease in the volume of steam inside it
Bcomplete trapping of heat inside it
Cincrease in the pressure of the pot
Ddecrease in the pressure of the pot
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Question 18
waec2008
Water of mass 1.5kg is heated from from 30oC to 80oC using an electric kettle which is rated 5A, 230V. Calculate the time taken to reach the final destination [specific heat capacity of water 4200Jkg-1K-1]
A4.57 minutes
B5.02 minutes
C7.30 minutes
D10.04 minutes
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Question 19
waec2008
The cubic expansivity of a certain gas at constant pressure is \(\frac{1}{273} k^{-1}\). If a given mass of the gas is held at constant pressure and its volume at 0oC is 273m3, determine the volume of the gas at 273oC.
A273m3
B546m3
C8193
D10923
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Question 20
waec2008
A metal rod of length 50cm is heated from 40oC to 80oC. If the linear expansivity of the material is \(\alpha\), calculate the increase in length of the rod (in metres) in terms of \(\alpha\)
A20\(\alpha\)
B200\(\alpha\)
C2000\(\alpha\)
D20000\(\alpha\)
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Question 21
waec2008
The design of the thermostat of an electric iron is based on the
Aemmision of electrons from metals when heated
Bincrease in size of metals when heated
Cincrease in the density of metals when heated
Dchange in the mass of metals when heated
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Question 22
waec2008
Which of the following equations for the efficiency of a machine is correct?
AEfficiency = \(\frac{\text{Velocity Ratio}}{\text{Mechanical Advantage}}\) x 100%
BEfficiency = \(\frac{input}{output}\) x 100%
CEfficiency = \(\frac{\text{load distance}}{\text{effort distance}}\) x 100%
DEfficiency = \(\frac{\text{Mechanical Advantage}}{\text{Velocity Ratio}}\) x 100%
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Question 23
waec2008
An object of mass 0.25kg moves at a height h above the ground with a speed of 4ms-1, if its mechanical energy at this height is 12 J, determine the value of h. [g = 10ms-1]
A0.8m
B4.0m
C4.8m
D5.6m
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Question 24
waec2008
Which of the following devices convert heat energy to electrical energy?
Atransformer
Bdynamo
Cthermocouple
Dthermostat
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Question 25
waec2008
A ball is dropped and it hits the floor at a point A. It rebounds upward to a point B. While moving from A to B its?
Akinetic energy is increasing
Bpotential energy is increasing
Cpotential energy is decreasing
Dkinetic energy remains constant
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Question 26
waec2008
An object of mass 2kg moving with a velocity 3ms-11 collides head-on with another object of mass 1kg moving in the opposite direction with a velocity of 4ms-1. If the objects stick together after collision, calculate their common speed.
A0.60ms-1
B0.67ms-1
C2.00ms-1
D3.33-1
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Question 27
waec2008
The mass attached to a string is moving in a circular path. If the speed is doubled, the tension in the string will be
Adoubled
Bhalved
Cfour times as great
Done-fourth as much
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Question 28
waec2008
The diagram above illustrates a bar magnet near a coil connected to a galvanometer, When the magnet is rapidly moves towards the coil i. e.m.f. is induced in the coil ii. the galvanometer needle deflects iii. the magnet is attracted by the coil. Which of the statements above is/are correct?
Ai only
Bii only
Ciii only
Di and iii only
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Question 29
waec2008
The diagram above represents the displacement-time graph of the motion of an object thrown upwards. The velocity of the object at the point P is
Amaximum
Buniform
Czero
Dterminal
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Question 30
waec2008
The diagram above illustrates a Hare's apparatus. \(\mathit{e}_1, \mathit{e}_2\) represent densities and \(\mathit{h}_1, \mathit{h}_2\) heights of columns of liquids. Which of the following equations is correct?
