JAMB and WAEC Physics questions

829 questions with answers and explanations. Tap an option to check yourself.

1. Question 81· Current electricity· JAMB

   Three resistors of 6 Ω each are connected in parallel. Their effective resistance is:

   • A18 Ω
   • B3 Ω
   • C2 Ω
   • D0.5 Ω

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   Explanation and discussion

2. Question 82· Current electricity· JAMB

   A Wheatstone bridge balances with P = 4 Ω, Q = 6 Ω and R = 10 Ω. Find the unknown resistance S.

   • A2.4 Ω
   • B6.7 Ω
   • C15 Ω
   • D20 Ω

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3. Question 83· Current electricity· JAMB

   

   In the circuit shown, the cell has negligible internal resistance. Find the total current drawn from the cell.

   • A2.0 A
   • B1.0 A
   • C0.2 A
   • D4.5 A

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4. Question 84· Current electricity· WAEC

   A current of 2 A flows through a resistor of 6 Ω. The potential difference across it is

   • A3 V
   • B12 V
   • C8 V
   • D4 V

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5. Question 85· Current electricity· WAEC

   Two resistors of 4 Ω and 12 Ω are connected in parallel. Their combined resistance is

   • A3 Ω
   • B16 Ω
   • C8 Ω
   • D0.33 Ω

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6. Question 86· Current electricity· WAEC

   A wire of resistance 10 Ω carries 2 A. The p.d. across it is

   • A0.2 V
   • B5 V
   • C12 V
   • D20 V

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7. Question 87· Current electricity· WAEC

   A galvanometer is converted to an ammeter by connecting

   • Aa low resistance in parallel (a shunt)
   • Ba high resistance in series
   • Ca capacitor
   • Da diode

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8. Question 88· Current electricity· JAMB

   Ohm's law states that, at constant temperature, the current through a conductor is proportional to the

   • Aresistance
   • Bpotential difference across it
   • Clength of the conductor
   • Dtime

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9. Question 89· Current electricity· JAMB

   Resistors of 2 Ω, 3 Ω and 5 Ω are connected in series to a 20 V supply. Find the current.

   • A4 A
   • B2 A
   • C10 A
   • D1 A

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10. Question 90· Current electricity· WAEC

    Ohm's law applies to a metallic conductor provided its

    • Atemperature stays constant
    • Blength changes
    • Ccurrent is a.c.
    • Dcolour is the same

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11. Question 91· Current electricity· WAEC

    A potentiometer is preferred to a voltmeter for measuring e.m.f. because it

    • Ais smaller
    • Bis cheaper
    • Cdraws no current at balance
    • Dhas a scale

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12. Question 92· Current electricity· WAEC

    A wire of resistance 8 Ω is cut into two equal halves, which are then joined in parallel. Find the new resistance.

    • A8 Ω
    • B4 Ω
    • C16 Ω
    • D2 Ω

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13. Question 93· Current electricity· JAMB

    For a metal conductor, as its temperature rises, its resistance

    • Aincreases
    • Bdecreases
    • Cstays the same
    • Dfalls to zero

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14. Question 94· Current electricity· JAMB

    A copper wire is 10 m long with cross-sectional area 1 × 10⁻⁶ m². Find its resistance. (Resistivity of copper = 1.7 × 10⁻⁸ Ω m)

    • A0.17 Ω
    • B1.7 Ω
    • C0.017 Ω
    • D17 Ω

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15. Question 95· Current electricity· WAEC

    Find the combined resistance of 4 Ω and 12 Ω resistors connected in parallel.

    • A16 Ω
    • B3 Ω
    • C8 Ω
    • D48 Ω

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16. Question 96· Current electricity· JAMB

    Resistors of 2 Ω, 3 Ω and 6 Ω are connected in parallel. Find their combined resistance.

    • A1 Ω
    • B11 Ω
    • C0.5 Ω
    • D3 Ω

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17. Question 97· Current electricity· WAEC

    What current flows through a 20 Ω resistor when the p.d. across it is 6 V?

    • A120 A
    • B0.3 A
    • C3.3 A
    • D26 A

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18. Question 98· Current electricity· JAMB

    A wire of resistance R is replaced by a wire of the same material with twice the length and half the cross-sectional area. Its resistance is

    • A2R
    • BR
    • C4R
    • DR/4

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19. Question 99· Current electricity· JAMB

    The resistivity of a material depends on

    • Athe nature of the material and its temperature
    • Bits length
    • Cits cross-sectional area
    • Dthe current

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20. Question 100· Current electricity· JAMB

    A Wheatstone bridge is balanced with P = 4 Ω, Q = 6 Ω and R = 10 Ω. Find the resistance S.

    • A15 Ω
    • B6.7 Ω
    • C2.4 Ω
    • D20 Ω

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    Explanation and discussion