(A) Gold
(B) Iron
(C) Diamond
(D) Quartz
The answer is: (C) Diamond
Diamond is the hardest known substance on the planet Earth.
Tag: physics mcqs
What is the SI unit of thermal conductivity?
(A) Joules
(B) Watts
(C) Joules per rho-Kelvin
(D) Watts per meter-Kelvin
The answer is: (D) Watts per meter-Kelvin
The SI unit of thermal conductivity watts per meter-Kelvin (W/m·K).
Which material has the highest thermal conductivity?
(A) Diamond
(B) Graphite
(C) Tungsten
(D) Silicon
The answer is: (A) Diamond
Thermal conductivity measures the ability of a material to
(A) store heat
(B) transfer heat
(C) store electricity
(D) transfer electricity
The answer is: (B) transfer heat
Thermal conductivity is a material’s ability to conduct heat. It measures how quickly heat can pass through a substance. The higher the thermal conductivity, the faster the heat transfer.
Which gas do plants absorb from the atmosphere for photosynthesis?
(A) Oxygen
(B) Nitrogen
(C) Carbon monoxide
(D) Carbon dioxide
The answer is: (D) Carbon dioxide
Plants primarily absorb carbon dioxide (CO2) from the atmosphere for photosynthesis. The photosynthesis is the process that plants use to convert light energy into chemical energy, which is stored in glucose (sugar). This process is essential for most life on Earth as it produces the oxygen we breathe.
What is the basic unit of life?
(A) Atom
(B) Organ
(C) Cell
(D) Tissue
The answer is: (C) Cell
The cell is the basic unit of life. It is the fundamental structural and functional unit of all known living organisms. All living things, whether a tiny bacterium or a massive whale, are made of one or more cells.
Which vitamin is produced in human skin in the presence of sunlight?
(A) Vitamin A
(B) Vitamin B
(C) Vitamin C
(D) Vitamin D
The answer is: (D) Vitamin D
The vitamin produced in human skin in the presence of sunlight is vitamin D.
When exposed to sunlight, a cholesterol-based compound in the skin called 7-dehydrocholesterol is converted into previtamin D3. This previtamin D3 then spontaneously transforms into vitamin D3, which is the form that is transported to the liver and kidneys to be converted into its active hormonal form.