Question:medium

The figure shows the revolution of the planet (P) around the sun (S) in an elliptical orbit. Which of the following statements is true regarding time taken?

Show Hint

Planets move faster when closer to the Sun (perihelion) and slower when farther away (aphelion).
Updated On: Jun 10, 2026
  • Time taken by the planet to travel BAD is less than that for DCB
  • Time taken by the planet to travel BAD is greater than that for DCB
  • Time taken by the planet to travel ADC is less than that for CBA
  • Time taken by the planet to travel ADC is greater than that for CBA
Show Solution

The Correct Option is B

Solution and Explanation

Step 1: Understand the setup.
A planet P moves around the Sun S in an oval (elliptical) orbit. We compare the time it takes along two arcs of the path, BAD and DCB.

Step 2: Recall Kepler's law of areas.
Kepler's second law says the line joining a planet to the Sun sweeps equal areas in equal times. So the planet sweeps area at a steady rate.

Step 3: Link speed to distance from the Sun.
Because of this law, the planet moves fast when it is close to the Sun and slow when it is far. Near the Sun it covers an arc quickly; far from the Sun it crawls.

Step 4: Identify the far arc.
The arc BAD lies on the side away from the Sun, the aphelion side. There the planet is slow.

Step 5: Identify the near arc.
The arc DCB lies on the side close to the Sun, the perihelion side. There the planet is fast.

Step 6: Compare the times.
Moving slowly over BAD takes longer than moving quickly over DCB. So the time for BAD is greater than the time for DCB. \[ \boxed{\text{Time for BAD} > \text{Time for DCB}} \]
Was this answer helpful?
0