According to Bohr's theory energy is ...when an electron moves from a lower to a higher orbit.

Options

A. Energy is released
B. Energy is absorbed
C. No change in energy
D. It radiations energy

Answer

To solve the question regarding Bohr's theory and the energy changes when an electron moves between orbits, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Orbits**:
- According to Bohr's model, electrons occupy specific energy levels or orbits around the nucleus of an atom. These orbits are designated by quantum numbers (n), where n1 is the lower energy level and n2 is the higher energy level.

2. **Energy Levels**:
- The energy of an electron in an orbit is quantized, meaning it can only exist in certain discrete energy levels. The energy of the orbit increases as the value of n increases (n2 > n1).

3. **Electron Transition**:
- When an electron transitions from a lower energy level (n1) to a higher energy level (n2), it must gain energy to make this transition.

4. **Energy Absorption**:
- To move to a higher energy level, the electron must absorb energy from an external source (like a photon). This process is termed as endothermic because energy is absorbed by the system (the electron).

5. **Conclusion**:
- Therefore, according to Bohr's theory, when an electron moves from a lower orbit to a higher orbit, energy is absorbed.

### Final Answer:
According to Bohr's theory, energy is **absorbed** when an electron moves from a lower to a higher orbit.

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