Verified Solution • 2025–26 Session moderate

QJEEM21Ph999d: JEE Main 2021 Physics - Class 11 JEEM21Ph999d Solution: A huge circular arc of length 4.4 ly subtends an angle '4s' at…

A huge circular arc of length 4.4 ly subtends an angle '4s' at the centre of the circle. How long it would take for a body to complete 4 revolution if its speed is 8 AU per second?

Given : 1 ly = 9.46 ×\times 1015 m

1 AU = 1.5 ×\times 1011 m

Multiple Choice Options

  • A 4.1 ×\times 108 s
  • B 4.5 ×\times 1010 s
  • C 3.5 ×\times 106 s
  • D 7.2 ×\times 108 s

Step-by-Step Verified Solution

R=lθR = {l \over \theta }

Time =4×2πRv=4×2πv(lθ)= {{4 \times 2\pi R} \over v} = {{4 \times 2\pi } \over v}\left( {{l \over \theta }} \right)

put l = 4.4 ×\times 9.46 ×\times 1015

v = 8 ×\times 1.5 ×\times 1011

θ=43600×π180\theta = {4 \over {3600}} \times {\pi \over {180}} rad.

we get time = 4.5 ×\times 1010 sec.

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