Answer:
Solar energy.
Step-by-step explanation:
Solar energy is the kind of energy that powers the devices when the solar radiations strike on the blades of the radiometer. The device has the ability to change or convert solar energy into mechanical energy. Solar radiation is a natural resource from which clean energy can be formed that can be used for different activities in our daily life. There are certain cells that are present on the body of radiometer that produces energy needed for its running.