When sound waves travel from one medium to another, the quantity which remains unchanged is its

A. speed

B. frequency

C. wavelength

D. All the above

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  1. The maximum range of most TV signals is from 121 to 240 km only because
  2. The mode of travel of heat energy from the sun across the empty space beyond the earth's atmosphere…
  3. A hydraulic brake in an automobile uses
  4. Atoms which have the same atomic number but different mass numbers are called
  5. A person does not sink in the Dead Sea because
  6. A photon is
  7. An astronomical unit of distance is
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  9. The planet that spins Caster than any other planet is
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  16. The property of a fluid by which it resists relative motion within itself is known as
  17. A proton is
  18. The electron has a mass equal to
  19. The attraction between similar molecules is called
  20. Chronometer la an instrument to measure
  21. Alternating Current (AC) is more advantageous than direct current because
  22. Primary colours are
  23. The cell that can be recharged, after it has run down, by passing a direct current through it from a…
  24. In experiments on static electricity the standard method for obtaining small amounts of positive electricity…
  25. SONAR (Sound Navigation Ranging) is
  26. The end product in the uranium disintegration series is
  27. The hydraulic jack to lift heavy vehicles in automobile service stations is one of the applications…
  28. When a light ray is reflected repeatedly by a set of parallel plane mirrors, the intensity of light…
  29. The principle of equivalence of mass and energy was established by
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