Which of the following statements about an electromagnet is not correct?
Ait is a temporary magnet
Bits strength depends on the current
Cits stength depends on the number of turns in its coil
Dit has permanent poles
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Question 1292
waec2003
The direction of induced current in a straight wire placed in magnetic field is determined by using?
AFleming's right hand rule
BMaxwell's screw rule
CFaraday's law
DLenz's law
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Question 1293
waec2003
One difference between a reactance and a resistance in an alternating current circuit is
Aresistance is larger than reactance
Benergy is not diaaipated in a reactance
Cenergy is stored in a resistance but not in a reactance
Dthe current in a reactance is lower than in the resistance
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Question 1294
waec2003
The maximum power dissipated by a 100\(\Omega\) resistor in a circuit is 4W. Calculate the voltage across the resistor
A10V
B20V
C25V
D400V
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Question 1295
waec2003
A lamp is rated 240V 60W, calculate the resistance of its filament
A240\(\Omega\)
B360\(\Omega\)
C960\(\Omega\)
D1440\(\Omega\)
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Question 1296
waec2003
A current of 10A passes through a conductor for 10s, calculate the charge flowing through the conductor
A100.0C
B10.0C
C1.0C
D0.1C
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Question 1297
waec2003
Which of the following factors does not affect the the electric resistance of a wire?
Alength
Bmass
Ctemperature
Dcross sectional area
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Question 1298
waec2003
Two identical cells each of e.m.f 2v and internal resistance 1.0\(\Omega\) are connected in parallel. The combination is connected to an external load of 1.5\(\Omega\). Calculate the current in the circuit
A0.57A
B1.00A
C1.14A
D2.00A
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Question 1299
waec2003
A positively charged glass rod is placed by near the cap of a positively charge electroscope. The divergence of the leaf is observed to
Adecrease
Bincrease
Cremain the same
Dincrease and collapse immediately
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Question 1300
waec2003
Which of the following statement about force is correct ?
Aelectrostatic, gravitational and magnetic forces are always attractive
Belectric, gravitational and magnetic field obeys inverse square law
Cfields are real but their corresponding field lines are imaginary
Dfield lines and their corresponding fields are both real
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Question 1301
waec2003
Which of the following features of an electrostatic line of force is not correct?
Ait is an imaginary line which a positive charge will describe if it is free to move
Bthe tangent drawn at any point on a curved line of force shows the direction of the electric field intensity at that point
Cit is sometimes curved
Dit can cross another line of force in a region of intense electric field
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Question 1302
waec2003
Which of the following instruments gives a pure note when sounded?
Atalking drum
Bsiren
Ctunning fork
Dguitar
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Question 1303
waec2003
A sonometer wire of linear density 0.08kg m-1 subjected to a tension of 800N is plucked. Calculate the speed of a pulse which moves from one end of the wire to the other
A179.0ms-1
B100.0ms-1
C15.8ms-1
D8.0ms-1
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Question 1304
waec2003
The speed of sound in air is is directly proportional to
Aits temperature on the celsius scale
Bite temperature in the thermodynamic scale
Cthe cube root of its temperature on its celcius csale
Dthe square roor of its temperature on the absolute scale
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Question 1305
waec2003
Which of the following statements about the human eye and the camera is correct?
Aboth form virtual image of objects
Bthe image formed by the eye is upright in the retina while that formed by the camera is inverted on the film
Cthe inside of both of them is blackened to absorb unwanted light
Dthe focal length of both eye lens and the camera lens can be varied
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Question 1306
waec2003
Which of the following pairs of rays shows the widest separation in the spectrum of white light?
Agreen and blue
Borange and indigo
Cblue and violet
Dred and yellow
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Question 1307
waec2003
A converging lens has a focal length of 5cm. Determine its power
A+20.0
B+0.2
C-20.00
D-0.2
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Question 1308
waec2003
The horizontal floor of a water reservoir appears to be 1.0m deep when viewed vertically from above. If the refractive index of water is 1.35, calculate the real depth of the reservoir
A2.35m
B1.35m
C1.00m
D0.35m
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Question 1309
waec2003
A converging lens produces an image four times as large as an object placed 25cm from the lens. Calculate its focal length
A100cm
B33cm
C29cm
D20cm
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Question 1310
waec2003
An object is placed on the principal axis and at the centre of curvature of a concave mirror, the image of the image formed by the mirror is
