JAMB Physics questions: Electrical energy and power

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

1. Question 1· Electrical energy and power· JAMB

   A 1.5 kW heater is used for 4 hours. If electricity costs ₦50 per kWh, find the cost.

   • A₦300
   • B₦75
   • C₦200
   • D₦6

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   Explanation and discussion

2. Question 2· Electrical energy and power· JAMB

   How many kilowatt-hours of energy does a 100 W bulb use in 10 hours?

   • A10 kWh
   • B1 kWh
   • C1000 kWh
   • D0.1 kWh

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   Explanation and discussion

3. Question 3· Electrical energy and power· JAMB

   A 13 A fuse is fitted in a 240 V circuit. What is the maximum power it allows?

   • A3,120 W
   • B18.5 W
   • C253 W
   • D31,200 W

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   Explanation and discussion

4. Question 4· Electrical energy and power· JAMB

   A 12 V supply is connected across a 6 Ω resistor. Find the power.

   • A72 W
   • B24 W
   • C2 W
   • D0.5 W

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   Explanation and discussion

5. Question 5· Electrical energy and power· JAMB

   In a household plug, the fuse should be connected in the

   • Ainsulation
   • Bneutral wire
   • Cearth wire
   • Dlive wire

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   Explanation and discussion

6. Question 6· Electrical energy and power· JAMB

   An electric heater rated 2 kW is used for 3 hours. The energy consumed is:

   • A6 kWh
   • B1.5 kWh
   • C0.67 kWh
   • D5 kWh

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   Explanation and discussion

7. Question 7· Electrical energy and power· JAMB

   A current of 2 A flows through a 5 Ω resistor for 10 s. Find the heat produced.

   • A100 J
   • B200 J
   • C20 J
   • D50 J

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8. Question 8· Electrical energy and power· JAMB

   A 60 W bulb is used on a 240 V supply. Find the current it draws.

   • A4 A
   • B0.25 A
   • C14 400 A
   • D0.5 A

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9. Question 9· 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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10. Question 10· 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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    Explanation and discussion

11. Question 11· 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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    Explanation and discussion

12. Question 12· 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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    Explanation and discussion

13. Question 13· 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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    Explanation and discussion