Ultraviolet radiation from the Sun is made up of three types. UVA is not stopped by the atmosphere. It penetrates through glass and goes the furthest into the skin. It causes wrinkles and brown spots on the skin. UVB is partially blocked by the atmosphere, it does not penetrate far into the skin but does cause sunburn. This leads to skin damage. UVC is highly dangerous but is stopped by the ozone layer. The UV index gives a forecast of the amount of UV daily. If the index reaches 3 then it is necessary to protect your skin. Many factors change the amount of UV that reaches you. Most UV passes through clouds so you can get sunburnt on a cloudy day. During the day most UV is present between 10am and 2pm. Different surfaces reflect UV, for example water, sand and snow are all very reflective. This means you can get sunburnt while sitting under an umbrella.
Well done ! You know lots about ultraviolet radiation. Remember to protect yourself when the UV index is above 3.
If you didn't get everything correct:Try again, or go back and read the information in the section about the UV index.