Bohr S Model For Hydrogen Atom

Step 1: Understanding the Question:
The question asks for the different energy components of an electron in the ground state ( ) of a hydrogen atom.
Step 2: Key Formula or Approach:
For a Bohr atom, the relationship between energies is:
1. Total Energy
2. For Hydrogen ground state,
Step 3: Detailed Explanation:
In the first orbit of Hydrogen ( ):
- Total Energy ( ): By Bohr's formula, . For , .
- Kinetic Energy ( ): Kinetic energy is always positive and .
- Potential Energy ( ): Potential energy is negative for an attractive system and .
Checking the options, (2) perfectly matches these calculations.
Step 4: Final Answer:
The correct set of energies is given in option (2).

Step 1: Understanding the Question:
The question refers to the specific physical quantity that is quantized according to Bohr's second postulate in his atomic model of hydrogen.
Step 3: Detailed Explanation:
Bohr's second postulate (also known as the quantum condition) states that an electron can revolve around the nucleus only in those fixed circular orbits for which its orbital angular momentum ( ) is an integral multiple of , where is Planck's constant.
Mathematically, this is expressed as:

where is the principal quantum number. This implies that angular momentum is not continuous but exists in discrete "packets" or quanta.
Step 4: Final Answer:
Bohr's second postulate implies the quantisation of angular momentum of an electron, which corresponds to option (3).