Answer:

If a planet is close to the Sun, the distance it orbits around the Sun is fairly short. This distance is called an orbital path. The closer a planet travels to the Sun, the more the Sun's gravity can pull on the planet. The stronger the pull of the Sun's gravity, the faster the planet orbits.

Why do planets have different periods of revolution around the sun?

If a planet is close to the Sun, the distance it orbits around the Sun is fairly short. This distance is called an orbital path. The closer a planet travels to the Sun, the more the Sun's gravity can pull on the planet. The stronger the pull of the Sun's gravity, the faster the planet orbits.

Hope it helps...