Question

If a new planet is discovered rotating around Sun with the orbital radius double that of earth, then what will be its time period (in earth's days)

• A. 1032
• B. 1023
• C. 1024
• D. 1043

Answer 1

Answer: (A)

1032

Answer 2

$T ^ { 2 } \propto R ^ { 3 }$ ⇒$\left( \frac { T _ { P } } { T _ { E } } \right) ^ { 2 } = \left( \frac { R _ { P } } { R _ { E } } \right) ^ { 3 } = \left( \frac { 2 R _ { E } } { R _ { E } } \right) ^ { 3 }$

⇒ $\frac { T _ { P } } { T _ { E } } = ( 2 ) ^ { 3 / 2 } = 2 \sqrt { 2 }$

⇒ $T _ { P } = 2 \sqrt { 2 } \times 365 = 1032.37$= 1032 days