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Sunday, 16 August 2026
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Physics Past Questions and Answers

Topic: Electrical Energy and Power

Jamb Physics Questions - Electrical Energy and Power

Question 1:
The electric supply from Kainji Dam is transmitted at high voltages of the order hundreds of kilovolts but is converted to domestic use of about 220 volts by
  • A Commutators
  • B Transistors
  • C Valves and diodes
  • D Rectifiers
  • E Transformers
View Answer & Explanation
Question 2:
The bulb of a motorcycle head-lamp is marked 40W, 6V. The resistance of the filament when it is switched on is
  • A \(\frac{6^2}{40^2}\)ohms
  • B \(\frac{40}{6^2}\)ohms
  • C \(\frac{40}{6}\)ohms
  • D 6 x 40 ohms
  • E \(\frac{6^2}{40}\)ohms
View Answer & Explanation
Question 3:
Which of the following statements on the use of X-rays is incorrect? X-rays are used
  • A In hospitals to obtain photogaphs of tissues and bones in the body
  • B For the treatment of malignant growths like cancer cells
  • C In detecting fingerprints
  • D To reveal hidden flaws in metal castings and welded joints
  • E To detect alternations which have been made to works of art
View Answer & Explanation
Question 4:
High Tension(H.T.) transmission means
  • A To transmit a given amount of power, the tension in the conducting wire must be high
  • B Heat is not lost when current is passed through a conductor
  • C Heat is gained when a given power is transmitted
  • D A big transformer is required to transmit power
  • E Trasmission of power at low current and high voltage
View Answer & Explanation
Question 5:
The resistance of a 240V, 60 watt electric filament bulb is
  • A 0.25\(\Omega\)
  • B 480\(\Omega\)
  • C 60\(\Omega\)
  • D 240\(\Omega\)
  • E 960\(\Omega\)
View Answer & Explanation