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Tuesday, 05 May 2026
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Physics Past Questions and Answers

Jamb Physics Questions

Question 76:
Which of the following statements is correct? The magnetized state of an iron bar can be destroyed completely by
  • A Heating the bar to a high temperature
  • B Breaking the bar
  • C Connecting opposite poles with a small piece of iron
  • D Placing the bar inside a strong magnetic field
  • E None of the above
View Answer & Explanation
Question 77:
An electric cell has an internal resistance of 2 ohms. A current of 0.5A is found to flow when a resistor of 5 ohms resistance is connected across it. What is the electromotive force of the cell?
  • A 5 volts
  • B 3.5 volts
  • C 2.5 volts
  • D 1 volts
  • E 10 volts
View Answer & Explanation
Question 78:
Which of the following is the correct definition of 'half-life'?
  • A The average life-time of a radioactive material
  • B The time it takes a radioactive material to decay to half of its original quantity
  • C Half the period a radioactive material decays completely
  • D Half of the decay constant
  • E The decay constant times life-time
View Answer & Explanation
Question 79:
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 80:
In an electrolysis experiment, a cathode of mass 5g is found o weigh 5.01g after a current of 5A flows for 50 seconds. What is the electrochemical equivalent of the deposited substance?
  • A 0.00004g/C
  • B 0.00002g/C
  • C 0.02500g/C
  • D 0.05000g/C
  • E 0.00001g/C
View Answer & Explanation