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Physics · UNITS AND MEASUREMENT

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As shown in the figure, plane angle \( d\theta \) is defined as the ratio of the length of arc \( ds \) to the radius \( r \). What is the SI unit for this plane angle?

Question diagram
  1. A
    steradian (sr)
  2. B
    radian (rad)
  3. C
    degree
  4. D
    radian per metre
View Answer & Solution

Correct answer · Option B

radian (rad)

Explanation

The unit for plane angle is radian with the symbol rad, which is a dimensionless quantity.

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