Answer:
The correct option is:
D) 589.3 nm
Explanation:
Energy of one photon = 

Hence, the wavelength (in nm) of radiation is 589.7nm (approximately equal to 589.3nm)
Answer:
The Two reasons are :-
1. Combustion efficiency
2. Standardization of test conditions as non-luminous flame.
Explanation:
A luminous flame isn't suitable for heating as it gives out soot (A black powdery or flaky substance consisting largely of amorphous carbon, produced by the incomplete burning of organic matter)
Atoms are the smallest form of the substance. examples of atoms are in elemental forms such as copper, helium, silver. Diatomic molecules are made up of identical atoms. Examples are I2.. F2 and Br2. Formula units are those compounds that are made up of two or more elements such as -No2, KMnO4,<span>C3H8, MgCl2, HgBr2, Ba(OH)2</span>
E and Dis determine the H