1. Which of the following are the ingredients of gun metal?
a) Iron, Zinc and Titanium
b) Iron and Tin
c) Iron, Brass and Tin
d) Copper, Tin and Zinc
Explanation: Modified gunmetal contains lead in addition to the zinc; it is typically composed of 86% copper, 9.5% tin, 2.5% lead, and 2% zinc. It is used for gears and bearings.
2. From which mineral is radium obtained?
Explanation: On April 20, 1902, Marie and Pierre Curie successfully isolate radioactive radium salts from the mineral pitchblende in their laboratory in Paris. In 1898, the Curies discovered the existence of the elements radium and polonium in their research of pitch blende.
3. What is laughing gas?
a) Nitrous Oxide
b) Carbon monoxide
c) Sulphur dioxide
d) Hydrogen peroxide
Explanation: Nitrous oxide, commonly known as laughing gas or nitrous, is a chemical compound, an oxide of nitrogen with the formula N2O
4.Actinides are the elements with atomic numbers from
a) 97 to 104
b) 101 to 115
c) 89 to 103
d) 36 from 43
Explanation: Actinides are the elements with atomic numbers from 89 to 103.
5. The two elements that are frequently used for making transistors are:
a) Boron and Aluminium
b) Silicon and Germanium
c) Iridium and Tungsten
d) Niobium and Columbium
Explanation: The two elements that are frequently used for making transistors are Silicon and Germanium.
6. The filament of an electric bulb is made of
Explanation: The filament of an electric bulb is made of Tungsten.
7. Diamond is an allotropic form of:
Explanation: Diamond and graphite are two allotropes of carbon: pure forms of the same element that differ in structure.
8. In fireworks, the green flame is produced because of
Explanation: In fireworks, the green flame is produced because of barium.
9. Permanent hardness of water can be removed by adding:
b) Washing Soda
c) Potassium Permanganate
d) Bleaching Powder
Explanation: Temporary hardness is due to presence of soluble bicarbonates of calcium and magnesium and permanent hardness is due to the presence of chlorides and sulphate of calcium and magnesium.
10. Marsh gas is
Explanation: Marsh gas, swamp gas, and bog gas is a mixture of methane, hydrogen sulfide, and carbon dioxide, produced naturally within some geographical marshes, swamps, and bogs.