Name the cell organelles concerned with trapping of solar energy.

Hint: It is a type of plastid that is found mostly in algae and green plants. It has a green pigment. It is distributed homogeneously throughout the cytoplasm of the cell. It ranges from \[20\] to \[40\] in a number in cells of higher plants. It contains double helix DNA, RNA and \[70s\] type ribosomes. The organelle is covered by a double membrane envelope and contains a matrix called stroma. It multiplies by fission from the pre-existing cells of its own. It is the organelle where trapping of light and photosynthesis takes place.

Complete answer:
Chloroplast is the organelle responsible for trapping solar energy. It is also the site of photosynthesis. The number of chloroplast ranges from \[20\] to \[40\] in plants. It has a double membrane envelope. The chloroplast is filled with a matrix called the stroma. It is a gel like fluid in which the granum is embedded. Granum is made up of a stack of thylakoids.
In thylakoids light reaction takes place. Solar energy is absorbed by the thylakoid membranes and converted into ATP and NADPH molecules. The converted molecules are used in dark reaction. Dark reaction takes place in the stroma. The reducing power of NADPH and the energy of ATP is utilized for the conversion of carbon dioxide into carbohydrate.
The carbohydrate produced is then transported throughout the plant by phloem.

Note:
Light reaction is also known as hill reaction and dark reaction is also known as Calvin reaction. Splitting of water during light reaction is the most important reaction. It results in the production of four electrons. Photosynthesis is an important characteristic of autotrophs.