Gold, which is not only the most valuable of metals, but also is without its peer in freedom from alloy, is known as the king of metals. Luxurious, classy and beautiful, gold is the most classic and coveted jewelry metal of all. It is also the oldest precious metal known to man.

Correct Option: A

Gold, which is not only the most valuable of metals, but also is without its peer in freedom from alloy, is known as the king of metals. Luxurious, classy and beautiful, gold is the most classic and coveted jewelry metal of all. It is also the oldest precious metal known to man.

In sequential order, Hydrogen, Oxygen, Carbon and Nitrogen are the most abundant elements by number in the living system. Hydrogen constitutes 49.8% of living systems, while Oxygen constitutes 24.9%; Carbon and Nitrogen account for 24.9% and 0.27% respectively. It is not surprising, therefore, that the living cell is between 60% and 90% water.

Correct Option: B

In sequential order, Hydrogen, Oxygen, Carbon and Nitrogen are the most abundant elements by number in the living system. Hydrogen constitutes 49.8% of living systems, while Oxygen constitutes 24.9%; Carbon and Nitrogen account for 24.9% and 0.27% respectively. It is not surprising, therefore, that the living cell is between 60% and 90% water.

The method of separation using magnets is used when one of the components is magnetic. So the heterogeneous mixture of iron filings and some other material (such as sulphur powder) can be separated by using magnets. Similarly, a mixture of sand and iron filings can be separated by magnet.

Correct Option: B

The method of separation using magnets is used when one of the components is magnetic. So the heterogeneous mixture of iron filings and some other material (such as sulphur powder) can be separated by using magnets. Similarly, a mixture of sand and iron filings can be separated by magnet.

The atomic radius is a measure of the size of an atom. It is defined as one-half the distance between the nuclei of two identical atoms that are bonded together. Angstrom is the most common unit used for measuring atomic radius. It is equivalent to 1.0 × 10¹⁰ meters. Under most definitions the radii of isolated neutral atoms range between 30 and 300 pm (trillionths of a metre), or between 0.3 and 3 angstroms.

Correct Option: C

The atomic radius is a measure of the size of an atom. It is defined as one-half the distance between the nuclei of two identical atoms that are bonded together. Angstrom is the most common unit used for measuring atomic radius. It is equivalent to 1.0 × 10¹⁰ meters. Under most definitions the radii of isolated neutral atoms range between 30 and 300 pm (trillionths of a metre), or between 0.3 and 3 angstroms.

Soaps are effective cleaners because they can dissolve and the oil and grease that holds dirt in place. They reduce the surface tension of the solution and enable it to wet things more uniformly. The surfactants in detergents improve water’s ability to wet things, spread over surfaces, and seep into dirty clothes fibers. The surfactant molecules help water to get a hold of grease, break it up, and wash it away.

Correct Option: B

Soaps are effective cleaners because they can dissolve and the oil and grease that holds dirt in place. They reduce the surface tension of the solution and enable it to wet things more uniformly. The surfactants in detergents improve water’s ability to wet things, spread over surfaces, and seep into dirty clothes fibers. The surfactant molecules help water to get a hold of grease, break it up, and wash it away.