When a potential difference, V is applied across the ends of a resistor of resistance, R a Current, l passes through the resistor. The heat generated in the resistor in time, t is given by the expression
AV2lt
BI2t/R
Cl2Rt
DlR2tR
EV2Rt
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Question 1832
waec1993
ln the diagram below, the galvanometer indicates a null-deflection. What is the potential difference between P and Q?
A0.0 V
B1.5 V
C2.0 V
D3.0V
E4.0 V.
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Question 1833
waec1993
Which of the following is not a conductor of electricity?
AHuman body
BGlass
CSilver
DEarth
ECopper
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Question 1834
waec1993
Calculate the current, I in the diagram shown above.
(Neglect the internal resistance of the cell)
A4.0A
B2.0A
C1.0A
DO.5A
E0.1A.
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Question 1835
waec1993
Electrical resistance is the property of an electrical conductor that causes electrical energy to be converted into
Amechanical energy
Bsolar energy
Cheat energy
Dmagnetic energy
Echemical energy.
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Question 1836
waec1993
In the diagram above, three identical lamps each of 100 W are connected in parallel across a potential difference of 250 V. Calculate the reading of the ammeter.
A7.5A
B2.5A
C1.2A
D0.8A
EO.4A
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Question 1837
waec1993
The function of the magnanese (IV) oxide in a leclanche cell is to
Adecrease the e.m.f. of the cell
Bprevent local action in the cell
Cprevent polarization in the cell
Dincrease the density of the electrolyte
Eincrease the resistance of the cell.
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Question 1838
waec1993
A particle of charge 5C moves perpendicularly to a magnetic Held of magnitude C.01 T. If the velocity of the charge is 1.5ms'2, calculate the magnitude of the force exerted on the particle
A0.050 N
B0.075N
C0.0300N
D3.300N
E0.000N
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Question 1839
waec1993
Which of the following have the greatest penetrating power?
ABeta rays
BAlpha rays
CGamma rays
DElectrons
ENeutrons
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Question 1840
waec1993
The potential difference between two points A and B situated at a distance d apart is V. Which of the following expresses the magnitude of the electric field intensity between the two points assuming the field is uniform?
AVd
BdV-1
CVd-1
DV2d
Ed2V
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Question 1841
waec1993
A point charge of 1.0 x 10-7 C experiences force of 0.01 N in a uniform electric field. Calculate the magnitude of the strength of the field
A106 Vm-1
B105 Vm-1
C10-5 Vm-1
D102 Vm-1
E109 Vm-1
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Question 1842
waec1993
In a purely resistive a.c. circuit, the current I = Io sin wt and voltage, V = Vo sin wt. Calculate the instantaneous power dissipated in the circuit in time t.
AIo Vo
B2Io Vosin wt
C(Io Vo)/2
DIo Vo sin2wt
EI2o V2o
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Question 1843
waec1993
The vector diagram shown below represents the resistance R, the capacitive reactance Xc, the inductive reactance Xc and the impedance, Z in an R-L-C circuit. The current in the circuit will be maximum when
AXL = XC
BXL = XL
CR = XL
DR = X
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Question 1844
waec1993
In a series R - C circuit, the resistance of the resistor is 4 Ω and capacitive reactance is 3 Ω. Calculate the impedance of the circuit
A1Ω
B4Ω
C5Ω
D7Ω
E12Ω
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Question 1845
waec1993
What is the gravitational potential due to a point mass m at a distance from it? (G = gravitational constant)
A-Gm2/r2
B-Gm2/r
C–Gm/Gr2
D–Gm/r
E–Gm/2
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Question 1846
waec1993
Calculate the escape velocity of a satellite launched from the earth’s surface (Take g as 10ms-2 and the radius of the earth as 6.4 x 106m)
A8.00 x 106ms-1
B1.13 x104ms-1
C3.58x102ms-1
D5.59 x10-2ms-1
E3.95x10-2ms-1
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Question 1847
waec1993
A household refrigerator consumes electrical energy at the rate of 200 W. lf electricity costs 5 k per kWh, calculate the cost of operating the appliance for 30 days.
AN7.20
BN12.00
CN30.00
DN33.33
EN72.00
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Question 1848
waec1993
The unit of inductance is
Afarad
Bhenry
Chertz
Dweber
Etesla
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Question 1849
waec1993
Which of the following instruments can be used to compare the relative magnitude of similar charges on two given bodies?
AElectrophorus
BEbonite rod
CProof plane
DGold-leaf electroscope
ECapacitor
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Question 1850
waec1993
Which of the following indicates the correct sequence of steps taken in charging a gold-leaf electroscope by induction? l. Removing the ebonite rod ll. Bringing a negatively charged ebonite rod close to the cap III. Earthing the cap IV. Disconnecting the earthing
