Tin/lead solders, also called soft solders, are commercially available with tin concentrations between 5% and 70% by weight. The greater the tin concentration, the greater the solder’s tensile and shear strengths. Alloys commonly used for electrical soldering are 60/40 Tin/lead (Sn/Pb) which melts at 370 °F or 188 °C and 63/37 Sn/Pb used principally in electrical/electronic work.

Correct Option: C

Tin/lead solders, also called soft solders, are commercially available with tin concentrations between 5% and 70% by weight. The greater the tin concentration, the greater the solder’s tensile and shear strengths. Alloys commonly used for electrical soldering are 60/40 Tin/lead (Sn/Pb) which melts at 370 °F or 188 °C and 63/37 Sn/Pb used principally in electrical/electronic work.

A transistor is a semiconductor device used to amplify and switch electronic signals and electrical power. Semiconductor material (date first used): the metalloids germanium (1947) and silicon (1954) — in amorphous, polycrystalline and mono-crystalline form; the compounds gallium arsenide (1966) and silicon carbide (1997), the alloy silicon-germanium (1989), the allotrope of carbon graphene (research ongoing since 2004), etc.

Correct Option: A

A transistor is a semiconductor device used to amplify and switch electronic signals and electrical power. Semiconductor material (date first used): the metalloids germanium (1947) and silicon (1954) — in amorphous, polycrystalline and mono-crystalline form; the compounds gallium arsenide (1966) and silicon carbide (1997), the alloy silicon-germanium (1989), the allotrope of carbon graphene (research ongoing since 2004), etc.

The Sun is a main-sequence star, and thus generates its energy by nuclear fusion of hydrogen nuclei into helium. Nuclear fusion is a nuclear reaction in which two or more atomic nuclei join together, or "fuse", to form a single heavier nucleus. During this process, matter is not conserved because some of the mass of the fusing nuclei is converted to photons which are released through a cycle that even our sun uses.

Correct Option: D

The Sun is a main-sequence star, and thus generates its energy by nuclear fusion of hydrogen nuclei into helium. Nuclear fusion is a nuclear reaction in which two or more atomic nuclei join together, or "fuse", to form a single heavier nucleus. During this process, matter is not conserved because some of the mass of the fusing nuclei is converted to photons which are released through a cycle that even our sun uses.

Gelatine, being a colloid, has the property of preventing crystallization. In ice lollies and ice-cream this is demonstrated by the formation of a very fine crystal structure on freezing. This goes much further in that gelatine stabilized ice-cream does not become grainy or sandy due to the slow crystallisation of lactose with time.

Correct Option: B

Gelatine, being a colloid, has the property of preventing crystallization. In ice lollies and ice-cream this is demonstrated by the formation of a very fine crystal structure on freezing. This goes much further in that gelatine stabilized ice-cream does not become grainy or sandy due to the slow crystallisation of lactose with time.

Oxalic acid is a reducing agent and its conjugate base, known as oxalate (C2O2–2), is a chelating agent for metal cations and stain removal. Oxalic acid's main applications include cleaning or bleaching, removal of stains on clothes and the removal of rust.

Correct Option: A

Oxalic acid is a reducing agent and its conjugate base, known as oxalate (C2O2–2), is a chelating agent for metal cations and stain removal. Oxalic acid's main applications include cleaning or bleaching, removal of stains on clothes and the removal of rust.