Answer: A. the transfer of heat by currents
Explanation: There are three modes of heat transfer:
1) Conduction: This type of heat transfer happens when there is direct contact between the two object. Example: heating a pan on stove.
2) Convection: This type of heat transfer happens when there is a movement of fluid (liquid or gas) due to the movement of hot layers to the top and cold layers to the bottom which leads to convection currents. Example: Heating of swimming pool.
3) Radiation: This type of heat transfer happens when there is direct transfer of energy through space. Example: Heating of earth's surface.
B. The transmission of heat across matter is conduction.
C. The electromagnetic radiation from the surface of an object which is due to the object's temperature is radiation.
D. The transmission of heat across empty space is radiation.
2 mol Al - 3 mol H₂SO₄
5 mol Al - x mol H₂SO₄
x=5*3/2=7.5
n(H₂SO₄)=7.5 mol
In a single displacement / replacement reaction a single uncombined element replaces another element in a compound.
Single replacement is type of chemical reaction where an element react with a compound and take the place of another element in that compound.
example of this type of reaction is
Zn+ 2HCl -----> Zncl2 + H2
Color implies visible light, so to answer your question: red light has the longest wavelength (~620 - 740 nm). However, there also exists light with even longer wavelengths that is not visible to the human eye, from infrared light to radio waves (with wavelengths that are meters long!)
Filtration, he used a mesh to filter out the stuff