Galvanization is the process of applying a protective zinc coating to steel or iron, in order to prevent rusting.

Correct Option: D

Galvanization is the process of applying a protective zinc coating to steel or iron, in order to prevent rusting.

Nichrome is used in electric iron because it has high resistance and it is stable in air when hot. Nichrome wire forms a protective layer of chromium oxide. Chemically it is quite stable and does not combine with other atmospheric gases even in high temperature.

Correct Option: C

Nichrome is used in electric iron because it has high resistance and it is stable in air when hot. Nichrome wire forms a protective layer of chromium oxide. Chemically it is quite stable and does not combine with other atmospheric gases even in high temperature.

The ozone layer is mainly found in the lower portion of the stratosphere from approximately 20 to 30 kilometres above Earth, though the thickness varies seasonally and geographically. Generally, it is smaller near the equator and larger towards the poles. It also varies with season, being in general thicker during the spring and thinner during the autumn in the northern hemisphere.

Correct Option: C

The ozone layer is mainly found in the lower portion of the stratosphere from approximately 20 to 30 kilometres above Earth, though the thickness varies seasonally and geographically. Generally, it is smaller near the equator and larger towards the poles. It also varies with season, being in general thicker during the spring and thinner during the autumn in the northern hemisphere.

Butanes are highly flammable, colourless, easily liquefied gases. When blended with propane and other hydrocarbons, it is referred to commercially as LPG, for liquefied petroleum gas.

Correct Option: D

Butanes are highly flammable, colourless, easily liquefied gases. When blended with propane and other hydrocarbons, it is referred to commercially as LPG, for liquefied petroleum gas.

The Sun is composed primarily of the chemical elements hydrogen and helium; they account for 74.9% and 23.8% of the mass of the Sun in the photosphere, respectively. All heavier elements, called metals in astronomy, account for less than 2% of the mass. The Sun inherited its chemical composition from the interstellar medium out of which it formed: the hydrogen and helium in the Sun were produced by Big Bang nucleosynthesis.

Correct Option: A

The Sun is composed primarily of the chemical elements hydrogen and helium; they account for 74.9% and 23.8% of the mass of the Sun in the photosphere, respectively. All heavier elements, called metals in astronomy, account for less than 2% of the mass. The Sun inherited its chemical composition from the interstellar medium out of which it formed: the hydrogen and helium in the Sun were produced by Big Bang nucleosynthesis.