Answer:
Jovian planets
Explanation:
The gas giants, or jovian or extra-terrestrial planets are predominantly made up of gases than liquids and solids.
They are located beyond the fringes of the Asteroid belts which is the zone between the inner and outer planets.
The outer planets are Jupiter, Saturn, Uranus and Neptune. These planets are made up of gases predominantly hydrogen and helium.
The inner planets called terrestrial planets are solids balls of rocks. These planets are Mercury, Venus, Earth and Mars.
The velocity of the wave on the string is given by
Solving the above equation,
The frequency of the wave 
and wave length is 
The velocity is 
Substituting numerical values,
The length of the string is 
