There is always an uncertainty involved in any attempt to measure the position and momentum of an electron simultaneously. This statement is known as the
Ade Broglie's law
BHeisenberg uncertainty principle
CFranck-Hertz experimental law
Dwave-particle paradox
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Question 442
waec2007
The correct sequence of energy transformation in the operation of an x-ray tube is i. X-rays ii. Kinetic energy of thermo electrons iii. Potential energy of the target atoms iv. Heat energy of the emitted electrons
Aiv, iii, ii, i
Bii, iv, iii, i
Civ, ii, iii, i
Diii, iv, ii, i
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Question 443
waec2007
In a nuclear reactor, chain reactions result from the release of
Aelectrons
Bphotons
Cneutrons
Dprotons
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Question 444
waec2007
The number of protons in an element increased by one after a radioactive decay. The element must have decay by emitting
Aa beta particle
Ban alpha particle
Ca gamma ray
Da neutron
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Question 445
waec2007
If a gas is excited by high voltage to produce a discharge and the light is examined in a spectrometer
Aan explosion is observed
Bthe rainbow colours are seen
Can emission spectrum is observed
Ddark lines are observed
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Question 446
waec2007
Which of the following electromagnetic wave can be detected by its heating effect?
Aultraviolet radiation
Bx-rays
Cgamma rays
Dinfrared radiation
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Question 447
waec2007
Five 80-W and three 100W are run for 8 hours. If the cost of energy is N5.00 per unit, calculate the cost of running the lamp. [1 unit = 1 kWh]
AN280.00
BN28.00
CN7.20
DN1.44
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Question 448
waec2007
A bulb marked 240V, 40W is used for 30 minutes. Calculate the heat generated
A320J
B400J
C10800J
D72000J
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Question 449
waec2007
Which of the following operations does not represent an action of a force field?
Afalling of a mango fruit from the tree
Bpicking of nails using a bar magnet
Crepulsion of two like charges
Dpushing of a wheel-barrow on a level gound
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Question 450
waec2007
Which of the following components is used for storing electric charges?
Ainductor
Bresistor
Ccapacitor
Delectrometer
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Question 451
waec2007
Which of the following statements is correct about resonance? Resonance occurs when a body
Avibrates with its natural frequency
Bis forced to vibrate on its own natural frequency by another body at the same vibration
Cvibrates at the frquency of the body causing the vibration
Dvibrates with an irregular frequency
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Question 452
waec2007
A dry plastic comb used in combing hair was found to attract pieces of paper and dust. The most probable explanation for this phenomenon is that the comb has been given
Amagnetization by induction
Belectric charges by induction
Celectric charges by conduction
Delectric charges by friction
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Question 453
waec2007
Which of the following statements about sound wave is not correct? Sound waves can be
Areflected
Brefracted
Cdiffracted
Dpolarized
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Question 454
waec2007
A sounding tuning fork is brought near the open end of a pipe containing air and the loudness of the sound is observed to increase. This observation is due to
Aan echo
Bresonance
Cinterference
Dreverbration
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Question 455
waec2007
Which of the following factors can affect the speed of sound in air? i. The temperature of the surrounding ii. The direction of the wind iii. The pitch of the sound.
Ai and ii only
Bii and iii only
Ci and iii only
Di, ii and iii
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Question 456
waec2007
A rectangular glass prism of thickness d and absolute refractive index n is placed on a point object which is viewed vertically downward from above the prism. Which of the following expressions correctly defines the apparent upward displacement of the object?
A\(\frac{d}{n}\)
Bdn
C\(\frac{d}{n - 2}\)
D\(\frac{d(n - 1)}{n}\)
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Question 457
waec2007
When an object is placed at the centre of curvature of a concave mirror, its image is formed at
Athe focus
Binfinity
Cthe centre of curvature
Da distance twice the radius of curvature
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Question 458
waec2007
In which of the following piece of apparatus is the radius of curvature equal to twice the focal length?
Aconverging lens
Bdiverging lens
Cconverging mirror
Dparabolic mirror
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Question 459
waec2007
An object is placed 10cm in front of a plane mirror. If it is moved 8cm away father away from the mirror, determine the distance of the final image from the mirror
A2cm
B9cm
C16cm
D18cm
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Question 460
waec2007
Which of the following phenomena is not a direct consequence of rectilinear propagation of light?
