JAMB and WAEC Physics questions

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

1. Question 181· Electrical energy and power· WAEC

   A kettle is rated 960 W, 240 V. Find its resistance.

   • A230,400 Ω
   • B4 Ω
   • C0.25 Ω
   • D60 Ω

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2. Question 182· Electrical energy and power· JAMB

   Find the resistance of a bulb rated 100 W, 220 V.

   • A0.45 Ω
   • B2.2 Ω
   • C484 Ω
   • D22 000 Ω

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3. Question 183· Electrical energy and power· WAEC

   If electricity costs ₦50 per kWh, running a 100 W bulb for 10 hours costs

   • A₦50
   • B₦500
   • C₦5
   • D₦5,000

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4. Question 184· Electrical energy and power· WAEC

   A 500 W electric iron is used for 4 hours. At ₦80 per kWh, find the cost.

   • A₦40
   • B₦1,600
   • C₦16
   • D₦160

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5. Question 185· Electrical energy and power· WAEC

   An electric iron rated 1,000 W is used for 2 hours. The energy used, in kilowatt-hours, is

   • A500 kWh
   • B2,000 kWh
   • C0.5 kWh
   • D2 kWh

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6. Question 186· Electrical energy and power· JAMB

   A 2 kW heater is used for 3 hours. How much energy does it use?

   • A0.67 kWh
   • B6 kWh
   • C1.5 kWh
   • D6,000 kWh

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7. Question 187· Electrical energy and power· WAEC

   A heater draws 5 A from a 220 V supply. Find its power.

   • A225 W
   • B44 W
   • C1100 W
   • D4400 W

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8. Question 188· Electrical energy and power· WAEC

   The fuse in a three-pin plug is connected in the

   • Aearth wire
   • Bneutral wire
   • Cany of the wires
   • Dlive wire

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9. Question 189· Electrical energy and power· JAMB

   A 2 kW electric iron is used for 5 hours. If electricity costs ₦70 per kWh, find the cost.

   • A₦70
   • B₦140
   • C₦350
   • D₦700

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10. Question 190· Electrical energy and power· JAMB

    A 2.4 kW electric kettle is used on a 240 V supply. The most suitable fuse is

    • A13 A
    • B3 A
    • C5 A
    • D30 A

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11. Question 191· Electrical energy and power· WAEC

    A 60 W bulb is used for 5 hours a day for 30 days. At ₦50 per kWh, what is the cost?

    • A₦4,500
    • B₦9,000
    • C₦15
    • D₦450

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12. Question 192· Electrical energy and power· JAMB

    A resistor gets hot when current flows because

    • Aelectrons collide with the atoms of the conductor
    • Bit is magnetic
    • Cit stores charge
    • Dit absorbs light

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13. Question 193· Electromagnetic induction· WAEC

    The iron core of a transformer is laminated in order to reduce

    • Aeddy current losses
    • Bthe resistance of the coils
    • Cthe flux linkage
    • Dthe output voltage

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14. Question 194· Electromagnetic induction· JAMB

    Faraday's law states that the induced e.m.f. is proportional to the

    • Arate of change of magnetic flux linkage
    • Bresistance of the coil
    • Ccurrent in the coil
    • Darea of the coil only

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15. Question 195· Electromagnetic induction· WAEC

    When a magnet's north pole is pushed into a coil, the induced current makes the near end of the coil a north pole. This illustrates

    • ALenz's law
    • BCoulomb's law
    • COhm's law
    • DNewton's first law

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16. Question 196· Electromagnetic induction· JAMB

    In a step-up transformer, the secondary coil has

    • Amore turns than the primary coil
    • Bfewer turns than the primary coil
    • Cthe same number of turns
    • Dno turns

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17. Question 197· Electromagnetic induction· WAEC

    Transformers do not work with direct current because

    • Ad.c. does not produce a changing magnetic field
    • Bd.c. is too strong
    • Cd.c. has no voltage
    • Dthe core melts

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18. Question 198· Electromagnetic induction· WAEC

    A transformer has 100 turns in the primary and 500 in the secondary. With 240 V input, the output is

    • A48 V
    • B1,200 V
    • C240 V
    • D600 V

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19. Question 199· Electromagnetic induction· JAMB

    A transformer has 200 turns in the primary and 1000 turns in the secondary. If the primary voltage is 40 V, the secondary voltage is:

    • A8 V
    • B400 V
    • C200 V
    • D5 V

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20. Question 200· Electromagnetic induction· WAEC

    The device that changes mechanical energy into electrical energy is the

    • Aelectric motor
    • Btransformer
    • Cgenerator
    • Dbattery

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    Explanation and discussion