The total energy of a revolving electron in any orbit is the sum of its kinetic and potential energies. Energy of an electron at infinite distance from the nucleus is zero. As an electron approaches the nucleus, the electron attraction increases and the energy of electron decreases and thus becomes negative. Thus, it can never be positive.

Correct Option: C

The total energy of a revolving electron in any orbit is the sum of its kinetic and potential energies. Energy of an electron at infinite distance from the nucleus is zero. As an electron approaches the nucleus, the electron attraction increases and the energy of electron decreases and thus becomes negative. Thus, it can never be positive.

Lead poisoning is a medical condition caused by increased levels of the heavy metal lead in the body. Lead interferes with a variety of body processes and is toxic to many organs and tissues including the heart, bones, intestines, kidneys, and reproductive and nervous systems. It interferes with the development of the nervous system and is therefore particularly toxic to children.

Correct Option: A

Lead poisoning is a medical condition caused by increased levels of the heavy metal lead in the body. Lead interferes with a variety of body processes and is toxic to many organs and tissues including the heart, bones, intestines, kidneys, and reproductive and nervous systems. It interferes with the development of the nervous system and is therefore particularly toxic to children.

As phenol is an aromatic alcohol, so FeCl₃ test is a test for alcohol and esterificaton test is also a test for alcohol. The ferric chloride test is used to determine the presence or absence of phenols in a given sample (for instance natural phenols in a plant extract).

Correct Option: C

As phenol is an aromatic alcohol, so FeCl₃ test is a test for alcohol and esterificaton test is also a test for alcohol. The ferric chloride test is used to determine the presence or absence of phenols in a given sample (for instance natural phenols in a plant extract).

The first modern photoflash bulb (or flashbulb) was made by Austrian Paul Vierkotter, who used magnesium coated wire in an evacuated glass globe. It was later determined that aluminum foil in a low pressure oxygen atmosphere worked even better, and was cheaper to produce.

Correct Option: C

The first modern photoflash bulb (or flashbulb) was made by Austrian Paul Vierkotter, who used magnesium coated wire in an evacuated glass globe. It was later determined that aluminum foil in a low pressure oxygen atmosphere worked even better, and was cheaper to produce.

Isoprene was first isolated by thermal decomposition of natural rubber. About 95% of isoprene production is used to produce cis-1,4polyisoprene—a synthetic version of natural rubber. Natural rubber consists mainly of poly-cis-isoprene with a molecular weight of 100,000 to 1,000,000.

Correct Option: A

Isoprene was first isolated by thermal decomposition of natural rubber. About 95% of isoprene production is used to produce cis-1,4polyisoprene—a synthetic version of natural rubber. Natural rubber consists mainly of poly-cis-isoprene with a molecular weight of 100,000 to 1,000,000.