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 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.

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.

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.

Fission as encountered in the modern world is usually a deliberately produced man-made nuclear reaction induced by a neutron. The nuclear fuels undergo fission when struck by fission neutrons, and in turn emit neutrons when they break apart. This makes possible a self-sustaining nuclear chain reaction that releases energy at a controlled rate in a nuclear reactor or at a very rapid uncontrolled rate in a nuclear weapon.

Correct Option: C

Fission as encountered in the modern world is usually a deliberately produced man-made nuclear reaction induced by a neutron. The nuclear fuels undergo fission when struck by fission neutrons, and in turn emit neutrons when they break apart. This makes possible a self-sustaining nuclear chain reaction that releases energy at a controlled rate in a nuclear reactor or at a very rapid uncontrolled rate in a nuclear weapon.