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Friday, 30 October 2026
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Physics Past Questions and Answers

Jamb 1990 Physics Questions

Question 16:
Which of the following statements? i. land and sea breezes are natural convection currents. ii. convection may occur in liquids or gasses but not in solids. iii. the vacuum in a thermos flask prevents heat loss due to convection only.
  • A I and ii only
  • B I and iii only
  • C I and iii only
  • D I, ii, and iii
View Answer & Explanation
Question 17:
A light wave of frequency 5 x 1014Hz moves through water which has a refractive index of \(\frac{4}{3}\). Calculate the wavelength in water if the velocity of light in air is 3 x 108ms-1
  • A 4.5 x 10<sup style='font-size: smaller;'>-7</sup>m
  • B 6.0 x 10<sup style='font-size: smaller;'>-7</sup>m
  • C 1.7 x 10<sup style='font-size: smaller;'>6</sup>m
  • D 2.2 x 10<sup style='font-size: smaller;'>6</sup>m
View Answer & Explanation
Question 18:
A wave disturbance travelling in air enters a medium in which its velocity is less than that in air. Which of the following statements is true about the wave medium?
  • A Both the frequency of the wave and the wavelength are decreased
  • B The frequency of the wave is decreased while the wavelength is increased
  • C The frequency of the wave is unaltered while the wavelength is decreased
  • D The frequency of the wave is decreased while the wavelength is unaltered
View Answer & Explanation
Question 19:
Shadows and eclipses result from the
  • A Refraction of light
  • B Rectilinear propagation of light
  • C Defraction of light
  • D Reflection of light
View Answer & Explanation
Question 20:
An object which is 3cm high is placed vertically 10cm in front of a concave mirror. If this object produces an image 40cm from the mirror, the height of the image is
  • A 0.75cm
  • B 4.00cm
  • C 8.00cm
  • D 12.00cm
View Answer & Explanation