A : The orbitals having equal energy are known as degenerate orbitals
R : The three 2p orbitals are degenerate in the presence of external magnetic field .

Options

A. IF both assertion & reason are true and the reason is the correct explanation of the assertion then mark
B. IF both assertion & reason are true but the reason is not the correct explanation of the assertion , then mark
C. IF assertion is true statement but reason is false , then mark
D. If both assertion and reason are false statements then mark

Answer

To analyze the given statements, we will break down the assertion (A) and the reason (R) step by step.

### Step-by-Step Solution:

1. **Understanding the Assertion (A)**:
- The assertion states that "The orbitals having equal energy are known as degenerate orbitals."
- This is a correct statement. In quantum mechanics, degenerate orbitals refer to orbitals that have the same energy level. For example, the three 2p orbitals (2p_x, 2p_y, 2p_z) are degenerate in the absence of any external fields.

2. **Understanding the Reason (R)**:
- The reason states that "The three 2p orbitals are degenerate in the presence of an external magnetic field."
- This statement is incorrect. When an external magnetic field is applied, the degeneracy of the orbitals is lifted, and the energy levels of the orbitals split. Therefore, the 2p orbitals will no longer have the same energy in the presence of a magnetic field.

3. **Conclusion**:
- Since the assertion is true and the reason is false, we can conclude that the correct relationship between the two statements is that the assertion is correct while the reason is incorrect.

### Final Answer:
- The assertion (A) is true, and the reason (R) is false.