JAMB Physics questions

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

1. Question 41· Current electricity· JAMB

   A wire has a resistance of 10 Ω. Another wire of the same material, twice as long and with twice the cross-sectional area, has a resistance of

   • A10 Ω
   • B20 Ω
   • C40 Ω
   • D5 Ω

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2. Question 42· Current electricity· JAMB

   A resistor of 5 Ω carries a current of 2 A. The potential difference across it is:

   • A2.5 V
   • B7 V
   • C10 V
   • D0.4 V

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3. Question 43· Current electricity· JAMB

   In a circuit, an ammeter is connected

   • Ain series, like a voltmeter
   • Bin parallel, and a voltmeter in series
   • Cin parallel, like a voltmeter
   • Din series, and a voltmeter in parallel

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4. Question 44· Current electricity· JAMB

   A charge of 60 C passes a point in a circuit in 2 minutes. The current is:

   • A30 A
   • B0.5 A
   • C120 A
   • D2 A

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5. Question 45· Current electricity· JAMB

   

   In the circuit shown, the battery has negligible internal resistance. Find the current through the 6 Ω resistor.

   • A3 A
   • B2 A
   • C1 A
   • D0.5 A

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6. Question 46· 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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7. Question 47· 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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8. Question 48· 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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9. Question 49· 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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10. Question 50· 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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11. Question 51· 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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12. Question 52· 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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13. Question 53· 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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14. Question 54· 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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15. Question 55· 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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16. Question 56· 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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17. Question 57· Dispersion of light and colours· JAMB

    Yellow light can be produced by mixing

    • Ared and blue light
    • Bred and green light
    • Cblue and green light
    • Dred and violet light

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18. Question 58· Dispersion of light and colours· JAMB

    A rainbow is formed by

    • Adiffraction by dust particles
    • Breflection of light from clouds
    • Crefraction, dispersion and internal reflection of sunlight in raindrops
    • Dabsorption of light by water vapour

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19. Question 59· Dispersion of light and colours· JAMB

    The primary colours of light are

    • Ared, yellow and blue
    • Bred, green and blue
    • Cred, orange and violet
    • Dyellow, cyan and magenta

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20. Question 60· Dispersion of light and colours· JAMB

    When white light passes through a prism, which colour is deviated most?

    • Ared
    • Bviolet
    • Cgreen
    • Dyellow

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    Explanation and discussion