Question

The earth revolves round the sun in one year. If the distance between them becomes double, the new period of revolution will be

• A. 1/2 year
• B. $2 \sqrt { 2 }$ years
• C. 4 years
• D. 8 years

Answer 1

Answer: (B)

$2 \sqrt { 2 }$ years

Answer 2

$\frac { T _ { 2 } } { T _ { 1 } } = \left( \frac { r _ { 2 } } { r _ { 1 } } \right) ^ { 3 / 2 } = ( 2 ) ^ { 3 / 2 } = 2 \sqrt { 2 }$ ⇒ $T _ { 2 } = 2 \sqrt { 2 }$ years.