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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 against ionizing radiation?
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Question and Solution 4 of 50
4. Question
4.
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Question and Solution 5 of 50
5. Question
5.
I. Low pressure II. High pressure III. High Potential Difference IV. Low Potential Difference
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 20×10^12F 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 potential difference 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 inductors 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 10KV, what is the wavelength of the associated electron? [Me = 9.1×10^34Kg, e = 1.6×10^19C , h = 6.6×10^34Js]
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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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