Silver bromide, a soft, pale-yellow, water insoluble salt well known for its unusual sensitivity to light. This property has allowed silver halides to become the basis of modern photographic materials.

Correct Option: B

Silver bromide, a soft, pale-yellow, water insoluble salt well known for its unusual sensitivity to light. This property has allowed silver halides to become the basis of modern photographic materials.

Titanium is the hardest natural metal in the world. It is very strong, three times the strength of steel and much stronger than gold, silver and platinum and yet is very light weight. Tungsten carbide is the hardest metal alloy on Earth and is scratch proof under normal wear. Tungsten carbide is two times as hard as steel and four times as hard as titanium.

Correct Option: D

Titanium is the hardest natural metal in the world. It is very strong, three times the strength of steel and much stronger than gold, silver and platinum and yet is very light weight. Tungsten carbide is the hardest metal alloy on Earth and is scratch proof under normal wear. Tungsten carbide is two times as hard as steel and four times as hard as titanium.

One end of a match is coated with a material that can be ignited by frictional heat generated by striking the match against a suitable surface. The coated end of a match, known as the match "head," contains either phosphorus or phosphorus sesquisulfide as the active ingredient and gelatin as a binder.

Correct Option: A

One end of a match is coated with a material that can be ignited by frictional heat generated by striking the match against a suitable surface. The coated end of a match, known as the match "head," contains either phosphorus or phosphorus sesquisulfide as the active ingredient and gelatin as a binder.

The main source of Naphthalene is coal-tar. Naphthalene is derived from a kind of naphtha which is a broad term encompassing any volatile, flamable liquid hydrocarbon mixture, including coal-tar.

Correct Option: C

The main source of Naphthalene is coal-tar. Naphthalene is derived from a kind of naphtha which is a broad term encompassing any volatile, flamable liquid hydrocarbon mixture, including coal-tar.

A solar cell (also called a photovoltaic cell) is an electrical device that converts the energy of light directly into electricity by the photovoltaic effect. Materials presently used for photovoltaic solar cells include mono-crystalline silicon, polycrystalline silicon, amorphous silicon, cadmium telluride, and copper indium selenide/sulfide.

Correct Option: B

A solar cell (also called a photovoltaic cell) is an electrical device that converts the energy of light directly into electricity by the photovoltaic effect. Materials presently used for photovoltaic solar cells include mono-crystalline silicon, polycrystalline silicon, amorphous silicon, cadmium telluride, and copper indium selenide/sulfide.