To answer this question, you need to understand the different types of radiation emitted by the sun. Let's go through each option to understand why it is correct or incorrect:
Option A) Visible radiation - This option is incorrect because visible radiation is a form of electromagnetic radiation that is visible to the human eye. It is not considered harmful.
Option B) Infra-red - This option is incorrect because infra-red radiation is also a form of electromagnetic radiation that is not considered harmful. In fact, it is commonly used in various applications such as remote controls and heat lamps.
Option C) Ultra-violet - This option is correct because ultra-violet (UV) radiation is a form of electromagnetic radiation that is emitted by the sun and can be harmful to living organisms. Prolonged exposure to UV radiation can lead to sunburn, skin damage, and an increased risk of skin cancer.
Option D) Radio waves - This option is incorrect because radio waves are a form of electromagnetic radiation that is not considered harmful. They are commonly used for communication purposes, such as radio broadcasts and cell phone signals.
The correct answer is C) ultra-violet. This option is correct because UV radiation emitted by the sun can be harmful to living organisms.