The diagram above shoes three forces F1, F2 and F3, which of the following ewuations is correct?
AF3 = F1 + F2
BF2 = F1 + F3
CF1 = F2 - F3
DF1 = F2 + F3
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Question 2
waec2008
A radioactive element has a decay constant of 0.077s-1. Calculate its half-life
A13.0s
B9.0s
C5.1s
D0.5s
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Question 3
waec2008
Control in nuclear reactors is effected with boron rods because rhe rods have the ability to
Aabsorb electrons
Babsorb neutron
Caccelerate electrons
Dslow down neutrons
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Question 4
waec2008
Nuclear fission is preffered to nuclear fusion in the generation of energy because
Avery high temperature are required for fusion
Bthe raw materials for fusion are easily obtained
Cenergy obtained from fusion is relatively small
Dthe by-products of fusion is very dangerous
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Question 5
waec2008
When a radioactive substance undergoes a beta decay, its
Amass number decreases by 1
Batomic number decreases by 1
Cmass number increases by 1
Datomic number increases by 1
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Question 6
waec2008
Both \(\gamma\)-rays and X-rays i. can be produced by thermionic emission ii. have low frequencies iii. have short wavelengths. Which of the statements above is/are correct?
Ai only
Bii only
Ciii only
Di and iii only
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Question 7
waec2008
A direct current of 5A flow through a 0.2H inductor. Calculate the energy stored in the inductor
A0.5J
B1.0J
C2.5J
D5.0J
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Question 8
waec2008
A transformer is required to supply 12 Vrms to operate a toy train set from a 240 Vrms. If the number of turns in the in the secondary coil is 100, calculate the number of turns required in the primary coil
A5
B12
C2000
D2400
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Question 9
waec2008
Fleming's right hand rule is also called the
Amotor rule
Bdynamo rule
Cscrew rule
Dthumb rule
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Question 10
waec2008
Which of the following actions will not increase the sensitivity of a moving coil galvanometer?
Ausing a strong temporary magnet
Bincreasing the area and number of turns of the coil
Cusing a week hair spring
Dusing a light pointer
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Question 11
waec2008
A voltmeter is a device that
Adraws high current
Bhas a very low resistance
Chas a very high resistance
Dis able to measure both voltage and current
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Question 12
waec2008
Three capacitors each of capacitance 1.5\(\mu F\) are connected in series. The total capacitance in the circuit is
A2.0 \(\mu F\)
B1.5 \(\mu F\)
C0.6 \(\mu F\)
D0.5 \(\mu F\)
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Question 13
waec2008
A wire 1.0m long and with cross-sectional area 2.0 x 10-7 m2 has a resistance of 0.1\(\Omega\). Calculate the electrical conductivity of the wire
A2.0 x 107\(\Omega^{-1} m^{-1}\)
B5.0 x 107\(\Omega^{-1} m^{-1}\)
C2.0 x 108\(\Omega^{-1} m^{-1}\)
D5.0 x 108\(\Omega^{-1} m^{-1}\)
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Question 14
waec2008
Which of the following is a unit of the time rate of flow of electric charges?
Acoulomb
Bampere
Cvolt
Dwatt
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Question 15
waec2008
If the charge on an object is measured as 4.0 x 10-18C, how many excess electrons does the object possess, given that the charge of an electron is 1.6 x 10-18C
A18
B19
C25
D37
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Question 16
waec2008
Two bodies each carrying a charge of 2.00 x 10-10C are 5cm apart. Calculate the magnitude of the force between the charges.[\(\frac{1}{4\pi \mathit{E}_o} = 9.00 \times 10^9 Nm^2C{-2}\)]
A1.44 x 10-7N
B7.20 x 10-9N
C7.20 x 10-11N
D1.44 x 1011N
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Question 17
waec2008
A negatively charged rod is held close to an uncharged metal ball on an insulating stand. The ball will
Abe negatively chargeed
Bbe positively charged
Chave an excess negatively charges on the side nearest the rod
Dhave an excess positively charges on the side nearest the rod
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Question 18
waec2008
a sound wave is produced fron a source ans an echo is heard t seconds afterwards. If d is the distance of the reflecting surface from the source, v the speed, p the wavelength and T the period of the wave, then
Ad = \(\frac{2t}{\lambda}\)
Bd = \(\frac{\lambda t}{2T}\)
Cd = \(\frac{2T}{\lambda t}\)
Dd = \(\frac{\lambda T}{2t}\)
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Question 19
waec2008
Which of the following defects of vision is as a result of the eye ball being too long?
Along sight
Bastigmatism
Cshort sight
Dloss of accommodation
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Question 20
waec2008
A converging lens and a screen are placed 20 cm and 80 cm respectively from an object in a straight line so that a sharp image of the object is formed on the screen. If the object is 3cm high. Calculate the height of the image formed
