Which of the following statements is not a reason for using soft iron in making the core of a transformer? It
Aretains its magnetism for a long time
Bis easily magnitised
Creduces energy loss due to hysteresis
Dis easily demagnetised
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Question 493
waec2005
Which of the following statements is an advantage of nuclear fusion over nuclear fission?
AThe resulting chain reaction which produces large amount of energy
Bno radioactve wave is produced as bye product
Cvery high temperature is required in the process
Dthe end product is lead
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Question 494
waec2005
an electric motor is a machine that converts
Amechanical energy into electrical energy
Belectrical energy into mechanical energy
Chigh voltage to low voltage
Dlow voltage to high voltage
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Question 495
waec2005
A bar magnet is placed near and lying along the axis of a solenoid connected to a galvanometer. The pointer of the galvanometer shows no deflection when
Athe magnet is moved away from the stationary solenoid
Bthe solenoid is moved away from the stationary magnet
Cthe magnet is moved towards the stationary solenoid
Dthere is no relative motion between the magnet and the solenoid
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Question 496
waec2005
Lenz's law of electromagnetic induction states that
Aa force is exerted on a current-carrying conductor in a magnetic field
Belectromotive force id induced in a circuit whenever there is a change in the magnetic flux linked with the circuit
Cthe magnitude of the induced electromotive force in a circuit is proportional to the rate of change of flux linking the circuit
Dthe induced current in a coil is in such a direction that it sets up a magnetic field which opposes the change producing it
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Question 497
waec2005
The mass and weight of a body on earth are 8kg and 80N respectively. Determine the mass and weight of the body respectively on a planet where the pull of gravity is \(\frac{1}{8}\) that on earth
A8kg, 8N
B1kg, 10N
C64kg, 10N
D8kg, 10N
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Question 498
waec2005
A constantan wire has a cross sectional area of 4 x 10-8m2 and a resistivity of 1.1 x 10-6\(\Omega\)m. If a resistor of resistance 11\(\Omega\) is to be made from this wire, calculate the length of the wire required
A0.4m
B0.8m
C2.5m
D5.0m
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Question 499
waec2005
Which of the following statements explains lost volt in an electric circuit? The
Atotal p.d from a source to maintain a flow of current through the circuit as well as the source
Bp.d to drive current through the circuit component except the source
Cp.d across all external components connected to the source of electricity
Dp.d across the internal resistance of the cell
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Question 500
waec2005
An electric lamp is rated 240V, 40W. What is the cost of running the lamp for 72 hours if the electricity authority charges N2.50 per kWh?
AN7.20
BN18.00
C180.00
DN720.00
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Question 501
waec2005
a chemical cell of internal resistance 1\(\Omega\) supplies electric current to an external resistor of resistance 3\(\Omega\). Calculate the efficiency of the cell
A75%
B50%
C33%
D25%
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Question 502
waec2005
A parallel plate capacitor of capacitance 600\(\mu F\) has a potential difference of 200V between its plates. Calculate the charge on either plate of the capacitor
A1.2C
B3.3C
C3330.0C
D12.0000.0C
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Question 503
waec2005
A parallel plate capacitor of capacitance 600\(\mu F\) has a potential difference of 200V between its plates. Calculate the charge on either plate of the capacitor
A1.2C
B3.3C
C3330.0C
D12.0000.0C
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Question 504
waec2005
Two capacitors if capacitance 0.4\(\mu F\) and 0.5\(\mu F\) are connected in parallel and charged to a p.d. of 50V, Determine the total charge acquired
A45\(\mu C\)
B25\(\mu C\)
C20\(\mu C\)
D10\(\mu C\)
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Question 505
waec2005
The ability of a material to store an electric charge when its plates are at different potentials is referred to as its
Aconductance
Binductance
Ccapacitance
Dresistance
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Question 506
waec2005
In which of the following media is the transmission of sound wave fastest?
AVacuum
BAir
CWood
DIron
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Question 507
waec2005
A ray of light is incident normally on a plan mirror. If the incident ray is kept fixed while the mirror is rotated through an angle of 30o, determine the initial and final angles of reflection respectively
A0o and 60o
B90o and 30o
C0o and 30o
D90o and 60o
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Question 508
waec2005
Which of the following optical instruments does not depend on the use of plane mirrors?
Akaleidoscope
Bsimple microscope
Csextant
Dsimple periscope
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Question 509
waec2005
The amplitude of a wave is the
Adistance travelled by the wave in a complete cycle of its motion
Bmaximum diplacement of the wave particle from the equilibrum position
Cseparation of two adjacent particles vibrating in a phase
Ddistance between two successive troughs of the wave
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Question 510
waec2005
Radio waves travel in air at 3.0 x 108ms-1. If the waves enter water of refractive index \(\frac{4}{3}\), calculate the speed of radio waves in water
