Everyday Science

The ozone layer is located in the stratosphere, which lies approximately 10 to 50 kilometers above the Earth's surface. This layer absorbs most of the Sun's ultraviolet radiation, protecting living organisms.

The Sun is a star because it is a massive, luminous sphere of plasma held together by gravity, producing energy through nuclear fusion. It is not a planet, comet, or satellite.

An Astronomical Unit (AU) is defined as the average distance between the Earth and the Sun, approximately 149.6 million kilometers. The other options refer to different astronomical distance measures or concepts.

When sound waves reflect off surfaces like floors, ceilings, or walls and mix with the original sound, causing a change in the sound's quality or complexion, this phenomenon is called reverberation. Echo refers to a distinct repetition of sound, not the blending effect described here.

The ozone layer absorbs most of the Sun's harmful ultraviolet (UV) radiation, protecting living organisms on Earth from its damaging effects. It does not protect against radioactive or infrared rays.

Hematite (Fe2O3) and Magnetite (Fe3O4) are the two most abundant natural iron oxides found in the Earth's crust. Pyrite is an iron sulfide, and bauxite is an aluminum ore, so they are not iron oxides.

A freely moving magnet aligns itself along Earth's magnetic field because Earth acts like a huge magnet with magnetic north and south poles. This causes the magnet to point towards the geographic north and south directions.

Light from the Sun takes approximately 8 minutes and 20 seconds to reach Earth, which is commonly rounded to 8 minutes. This is because the average distance from the Sun to Earth is about 150 million kilometers, and light travels at about 300,000 kilometers per second.

The standard unit for measuring home electricity energy consumption is the kilowatt hour (kWh), which represents the energy used when a 1-kilowatt device runs for one hour. This unit is commonly used by electricity providers for billing purposes.

The average distance from the Sun to the Earth is approximately 150 million kilometers, which is why option C is correct. This distance is also known as 1 Astronomical Unit (AU).