1. Which one/s of the following is/are NOT an electromagnetic wave?

(a) Microwaves.

(b) X-rays.

(c) Sound waves.

(d) Light.

(e) Radio waves.

(f) earthquakes.

Answer: Sound Waves and earthquakes.

2. Explain in short "the greenhouse effect" regarding our atmosphere. The exhaust gases from automobiles and the burning of fossil fuels contain CO2 and water vapor which are released into Earth's atmosphere. The infrared radiation from the Sun gets absorbed by Earth and then re-emitted, but instead of going back into space get's re-absorbed by these greenhouse gases (CO2 and water vapor) which act as a blanket around Earth's atmosphere. This results in raising the Earth's temperature. This is known as the "greenhouse effect".

3. What are CFC's and what effect do they have on our atmosphere? CFC's stand for Chlorofluorocarbons. They are gases like Freon, and are available in the aerosol sprays. Through chemical reactions they break up the Ozone layer on Earth's upper atmosphere creating Ozone wholes; Ozone protects us from the ultraviolet rays from the Sun.