In printing, type metal (sometimes called hot metal) refers to the metal alloys used in traditional typefounding and hot metal typesetting. Lead is the main constituent of these alloys. Antimony and tin are added to make the character produced durable and tough while reducing the difference between the coefficients of expansion of the matrix and the alloy. Cheap, plentifully available as galena and easily workable, lead has many of the ideal characteristics, but on its own it lacks the necessary hardness and does not make castings with sharp details because molten lead shrinks and sags when it cools to a solid.

Correct Option: B

In printing, type metal (sometimes called hot metal) refers to the metal alloys used in traditional typefounding and hot metal typesetting. Lead is the main constituent of these alloys. Antimony and tin are added to make the character produced durable and tough while reducing the difference between the coefficients of expansion of the matrix and the alloy. Cheap, plentifully available as galena and easily workable, lead has many of the ideal characteristics, but on its own it lacks the necessary hardness and does not make castings with sharp details because molten lead shrinks and sags when it cools to a solid.

The greenhouse effect is a process by which thermal radiation from a planetary surface is absorbed by atmospheric greenhouse gases, and is re-radiated in all directions. Since part of this re-radiation is back towards the surface and the lower atmosphere, it results in an elevation of the average surface temperature above what it would be in the absence of the gases. By their percentage contribution to the greenhouse effect on Earth the four major gases are: water vapor, 36–70%, carbon dioxide, 9– 26%,methane, 4–9% and ozone, 3–7%.

Correct Option: B

The greenhouse effect is a process by which thermal radiation from a planetary surface is absorbed by atmospheric greenhouse gases, and is re-radiated in all directions. Since part of this re-radiation is back towards the surface and the lower atmosphere, it results in an elevation of the average surface temperature above what it would be in the absence of the gases. By their percentage contribution to the greenhouse effect on Earth the four major gases are: water vapor, 36–70%, carbon dioxide, 9– 26%,methane, 4–9% and ozone, 3–7%.

Sublimation apparatus is a piece of laboratory glassware used in the technique of sublimation usually used by chemists to purify compounds. Typically a solid is placed in a vessel which is then heated under vacuum. Under this reduced pressure the solid volatilizes and condenses as a purified compound on a cooled surface, leaving the non-volatile residue impurities behind. This cooled surface often takes the form of a cold finger. Once heating ceases and the vacuum is released, the sublimed compound can be collected from the cooled surface. Impure camphor is purified by this process.

Correct Option: A

Sublimation apparatus is a piece of laboratory glassware used in the technique of sublimation usually used by chemists to purify compounds. Typically a solid is placed in a vessel which is then heated under vacuum. Under this reduced pressure the solid volatilizes and condenses as a purified compound on a cooled surface, leaving the non-volatile residue impurities behind. This cooled surface often takes the form of a cold finger. Once heating ceases and the vacuum is released, the sublimed compound can be collected from the cooled surface. Impure camphor is purified by this process.

Electrolysis is a method of using a direct electric current (DC) to drive an otherwise non-spontaneous chemical reaction. Electrolysis is commercially highly important as a stage in the separation of elements from naturally occurring sources such as ores using an electrolytic cell. Aluminum is extracted from its oxide ore “Bauxite”. Electrolytic smelting of alumina was originally cost-prohibitive in part because of the high melting point of alumina, or aluminium oxide. Many minerals, however, will dissolve into a second already molten mineral, even if the temperature of the melt is significantly lower than the melting point of the first mineral. Molten cryolite was discovered to dissolve alumina at temperatures significantly lower than the melting point of pure alumina without interfering in the smelting process.

Correct Option: C

Electrolysis is a method of using a direct electric current (DC) to drive an otherwise non-spontaneous chemical reaction. Electrolysis is commercially highly important as a stage in the separation of elements from naturally occurring sources such as ores using an electrolytic cell. Aluminum is extracted from its oxide ore “Bauxite”. Electrolytic smelting of alumina was originally cost-prohibitive in part because of the high melting point of alumina, or aluminium oxide. Many minerals, however, will dissolve into a second already molten mineral, even if the temperature of the melt is significantly lower than the melting point of the first mineral. Molten cryolite was discovered to dissolve alumina at temperatures significantly lower than the melting point of pure alumina without interfering in the smelting process.

Pasteurization typically uses temperatures below boiling, since at very high temperatures, casein micelles will irreversibly aggregate, or “curdle”. The two main types of pasteurization used today are: hightemperature, short-time (HTST) and “extended shelf life” (ESL) treatment. Ultra-high temperature (UHT or ultra-heat-treated) is also used for milk treatment. In the HTST process, milk is forced between metal plates or through pipes heated on the outside by hot water, and is heated to 71.7degree C (161degree F) for 15– 20 seconds. UHT processing holds the milk at a temperature of 135degree C (275degree F) for a minimum of one second. ESL milk has a microbial filtration step and lower temperatures than UHT milk. Milk simply labeled “pasteurized” is usually treated with the HTST method, whereas milk labeled “ultrapasteurized” or simply “UHT” has been treated with the UHT method. A less conventional but US FDAlegal alternative (typically for home pasteurization) is to heat milk at 145 degree F (63 degree C) for 30 minutes.

Correct Option: B

Pasteurization typically uses temperatures below boiling, since at very high temperatures, casein micelles will irreversibly aggregate, or “curdle”. The two main types of pasteurization used today are: hightemperature, short-time (HTST) and “extended shelf life” (ESL) treatment. Ultra-high temperature (UHT or ultra-heat-treated) is also used for milk treatment. In the HTST process, milk is forced between metal plates or through pipes heated on the outside by hot water, and is heated to 71.7degree C (161degree F) for 15– 20 seconds. UHT processing holds the milk at a temperature of 135degree C (275degree F) for a minimum of one second. ESL milk has a microbial filtration step and lower temperatures than UHT milk. Milk simply labeled “pasteurized” is usually treated with the HTST method, whereas milk labeled “ultrapasteurized” or simply “UHT” has been treated with the UHT method. A less conventional but US FDAlegal alternative (typically for home pasteurization) is to heat milk at 145 degree F (63 degree C) for 30 minutes.