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Question and Solution 1 of 50
1. Question
1. A transistor functions mainly as a
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Question and Solution 2 of 50
2. Question
2. The process of energy production in the sun is
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Question and Solution 3 of 50
3. Question
3. Which of the following metals will provide the greatest shield ionizing radiation?
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Question and Solution 4 of 50
4. Question
4. The particle emitted when 3919K decay to 3919K is
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Question and Solution 5 of 50
5. Question
I. pressure II. High pressure III. High P.D IV. Low P.D
Which combination of the above is true of the conduction of electricity through gases?CorrectIncorrect 
Question and Solution 6 of 50
6. Question
6.
Which of the following graphs correctly represents the variation of mass of a given material deposited with time for constant current in faraday’s law of electrolysis?
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Question and Solution 7 of 50
7. Question
7. The current through a resistor in an a.c. circuit is given as 2sinwt. Determine the d.c. equivalent of the current.
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Question and Solution 8 of 50
8. Question
8. At resonance, the phase angle in an a.c. circuit is
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Question and Solution 9 of 50
9. Question
9. Energy losses through eddy currents are reduced by using:
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Question and Solution 10 of 50
10. Question
10. A capacitor of 20x1012F and an inductor are joined in series. The value of the inductance that will give the circuit a resonant frequency of 200KHz is ?
[π^2 = 10]
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Question and Solution 11 of 50
11. Question
11. In the diagram below, determine the r.m.s current
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Question and Solution 12 of 50
12. Question
12. The primary coil of a transformer has Nturns and is connected to a 120V a.c. power line. If the secondary coil has 1000 turns and a terminal voltage of 1200 volts. What is the value of N?
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Question and Solution 13 of 50
13. Question
13. The force on a currentcarrying conductor in a magnetic field is greatest when the
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Question and Solution 14 of 50
14. Question
14. The magnetic force on a charged particle moving with velocity V is
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Question and Solution 15 of 50
15. Question
15. A working electric motor takes a current of 1.5A when the p.d across it is 250V. if its efficiency is 80%, the power output is
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Question and Solution 16 of 50
16. Question
16. A bread toaster uses a current of 4A when plugged in a 240 volts line. It takes one minute to toast slices of bread. What is the energy consumed by the toaster?
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Question and Solution 17 of 50
17. Question
17. The cost of running five 60W lamps and four 100W lamps for 20hours if electrical energy costs ₦10.00 per kWh
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Question and Solution 18 of 50
18. Question
18. The diagram below shows three capacitors C_{1}, C_{2}, C_{3} of capacitance 2F, 6F, and 3F respectively. The potential differences across C_{1}, C_{2 }and C_{3} respectively are;
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Question and Solution 19 of 50
19. Question
19. When a piece of rectangular glass block is inserted between two parallel plate capacitors, at constant plate area and distance of separation, the capacitances of the capacitor will
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Question and Solution 20 of 50
20. Question
20. Zener diode is used for
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Question and Solution 21 of 50
21. Question
21
Given three inductor of inductance 5mH 10mH and 20mH connected in series, the effective inductance is
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Question and Solution 22 of 50
22. Question
22. If electrons are accelerated from rest through a potential difference of 90KV, what is the wavelength of the associated electron? [Me = 9.1×1034Kg, e = 1.6×1019C , h = 6.6×1034Js]
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Question and Solution 23 of 50
23. Question
23.
In the diagram below, the current I is
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Question and Solution 24 of 50
24. Question
24.
In the circuit diagram below, the ammeter reads a current of 3A when R is 5Ω and 6A when R is 2Ω. Determine the value of x
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Question and Solution 25 of 50
25. Question
25.
A resistance R is connected across the terminal of an electric cell of internal resistance 2Ω and the voltage was reduced to of its nominal value. This value of R is
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Question and Solution 26 of 50
26. Question
26. What is the angle of dip at the magnetic equator?
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Question and Solution 27 of 50
27. Question
27. The terrestrial telescope has one extra lens more than the astronomical telescope. The extra lens is for:
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Question and Solution 28 of 50
28. Question
28. The colours seen in soap bubbles are due to
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Question and Solution 29 of 50
29. Question
29. To produce an enlarged and erect image with a concave mirror, the object must be positioned
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Question and Solution 30 of 50
30. Question
30. A concave mirror of radius of curvature 40cm forms a real image twice as large as the object. The object distance is
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Question and Solution 31 of 50
31. Question
31. The energy stored in a capacitor of capacitance 10μF carrying a charge of 100μC is
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Question and Solution 32 of 50
32. Question
32. The electromagnetic wave that can produce a heating effect on the environment is
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Question and Solution 33 of 50
33. Question
33. Calculate the refractive index of the material for the glass prism in the diagram below
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Question and Solution 34 of 50
34. Question
34. At what frequency would a capacitor of 2.5μF used in a radio circuit have a reactance of 250Ω?
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Question and Solution 35 of 50
35. Question
35.
What particles is X in the reaction above?
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Question and Solution 36 of 50
36. Question
36. The particle that is responsible for nuclear fission in a nuclear reactor is
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Question and Solution 37 of 50
37. Question
37. The carbongranule microphone works on the principle of change in
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Question and Solution 38 of 50
38. Question
38. The eyes control the amount of light reaching the retina by adjusting the
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Question and Solution 39 of 50
39. Question
39.
The electric field between twopoint charges is shown in the diagram above.
What types of charges are at X and Y?
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Question and Solution 40 of 50
40. Question
40. A current of 0.5A flowing for 3hours deposits 2g of metal during electrolysis. The quantity of the same metal that would be deposited by a current of 1.5A flowing in hours is
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Question and Solution 41 of 50
41. Question
41. The energy associated with the photon of radio transmission at 3x105Hz is [h = 6.63×1034Js]
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Question and Solution 42 of 50
42. Question
42. The percentage of the original nuclei of a sample of a radioactive substance left after 5 halflives is
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Question and Solution 43 of 50
43. Question
43. From the generating station to each substation power is transmitted at a very high voltage so as to reduce
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Question and Solution 44 of 50
44. Question
44.
Which of the following graphs shows the correct vector diagram for the circuit above?
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Question and Solution 45 of 50
45. Question
45. Pure silicon can be converted to a ptype material by adding a controlled amount of
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Question and Solution 46 of 50
46. Question
46. When alternating current given by I = 10sin(120πt) passes through a 12Ω resistor, the power dissipated in the resistor is
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Question and Solution 47 of 50
47. Question
47. The maximum kinetic energy of the photoelectrons emitted from a metal surface is 0.34eV. if the work function of the metal surface is 1.83eV, find the stopping potential
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Question and Solution 48 of 50
48. Question
48. The force on a charge moving with velocity V in a magnetic field B is half of the maximum force when the angle between V and B is
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Question and Solution 49 of 50
49. Question
49. The count rate of radioactive material is 800 count/min. If the halflife of the material is 4 days, what would the count rate be 16days later?
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Question and Solution 50 of 50
50. Question
50. In a semiconductor junction diode, as the depletion or barrier layer is forwardbiased, the layer
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