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 432
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 433
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 434
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 435
waec2008
Which of the following devices convert heat energy to electrical energy?
Atransformer
Bdynamo
Cthermocouple
Dthermostat
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Question 436
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 437
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 438
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 439
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 440
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 441
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?
A very sensitive spring balance was used to determine the weight of an object at the north pole. When the same spring balance was used to measure the weight of the same object at the equator, it was found to reduce. The explanation for this observation is that
Ait is very hot at the equator
Bthe spring balance has expanded
Cthe acceleration of free fall due to gravity varies with location
Dthe mass of the body is reduced
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Question 443
waec2008
A rectangular block of dimensions 2.0m x 1.0m x 0.5m weighs 200N. calculate the maximum pressure exerted by the block on a horizontal floor.
A100Nm-2
B200Nm-2
C300Nm-2
D400Nm-2
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Question 444
waec2008
A car travelling with a uniform velocity of 30ms-1 along a horizontal road overcomes a constant frictional force of 600N. Calculate the power of the engine of the car
A18kW
B20kW
C180kW
D200kW
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Question 445
waec2008
Which of the following is/are in random motion? i. Pollen grains in water ii. The molecules of hydrogen gas ii. Fine chalk particles floating in air
Ai and ii only
Bi and iii only
Cii and iii only
Di, ii and iii
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Question 446
waec2008
which of the following statements about Archimedes' principle is correct? The upthrust on a body is a measure of the
Amass of fluid displaced
Bweight of the body
Cvolume of the body
Dweight of the fluid displaced
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Question 447
waec2008
Which of the following sets of quantities is fundamental?
Alength, mass and time
Bspeed, length and time
Cspeed, mass and distance
Ddistance, speed and time
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Question 448
waec2008
If the air inside a rigid box is heated, the i, average speed of the molecules increases ii. pressure of the air increases iii. average separation of the molecule increases. Which of the statements above are correct?
Ai and ii only
Bii and iii only
Ci and iii only
Di, ii and iii
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Question 449
waec2007
Calculate the effective resistance between P and Q in the diagram above
A0.75\(\Omega\)
B4.00\(\Omega\)
C5.00\(\Omega\)
D7.00\(\Omega\)
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Question 450
waec2007
The diagram above illustrates three forces acting on an object at point O. If the object is in equilibrium, determine the magnitude of the force P.
