In which transition, one quantum of energy is emitted -

Options

A. `n=4 rarr n=2`
B. `n=3 rarr n=1`
C. `n=4 rarr n=1`
D. `n=2 rarr n=1`

Answer

To solve the question of which transition emits one quantum of energy, we need to understand the concept of energy transitions in atomic structure. Here’s a step-by-step breakdown of the solution:

### Step 1: Understand Quantum Energy
- **Definition**: A quantum of energy refers to the smallest discrete amount of energy that can be emitted or absorbed by an atom during a transition between energy levels.
- **Formula**: The energy associated with a quantum is given by the equation \( E = h \nu \), where \( E \) is the energy, \( h \) is Planck's constant, and \( \nu \) is the frequency of the emitted radiation.

### Step 2: Identify Energy Transitions
- **Energy Levels**: Atoms have quantized energy levels, meaning electrons can only exist in specific energy states. When an electron transitions from a higher energy level to a lower energy level, energy is emitted.
- **Transitions**: The transitions can be represented as follows:
- Transition from a higher shell (n=4) to a lower shell (n=2).
- Transition from a higher shell (n=3) to a lower shell (n=1).
- Transition from a higher shell (n=2) to a lower shell (n=1).

### Step 3: Determine Energy Emission
- **Higher to Lower Transition**: In each of the transitions mentioned, energy is emitted when an electron moves from a higher energy level to a lower energy level.
- **Emission of One Quantum**: Each transition emits one quantum of energy, which corresponds to the difference in energy between the two levels involved in the transition.

### Step 4: Conclusion
- **All Options Emit Energy**: Since all the transitions described involve moving from a higher energy level to a lower energy level, they all result in the emission of one quantum of energy.
- **Final Answer**: Therefore, the answer to the question is that in all cases provided, one quantum of energy is emitted.