NextMockதேர்வுகளைத் தேடுங்கள், எ.கா. SSC CGL, UPPSC, Lekhpal
UPSC PYQPrelims 2021

Civil Services Examination · வினா 76

Which one of the following is a reason why astronomical distances are measured in light-years?

  1. Distances among stellar bodies do not change.
  2. Gravity of stellar bodies does not change.
  3. Light always travels in straight line.
  4. Speed of light is always same.
விடையைக் காட்டு & விளக்கம்

விடை: (D) Speed of light is always same.

விளக்கம்

The speed of light in vacuum is constant, so the distance light travels in a year is a fixed, convenient unit.