Assertion (A): It is impossible to determine the exact position and exact momentum of an electron simultaneously.
Reason (R): The path of an electron in an atom is clearly defined. 

  

1. Both (A) and (R) are True and (R) is the correct explanation of (A).
2. Both (A) and (R) are True but (R) is not the correct explanation of (A).
3. (A) is True but (R) is False.
4. (A) is False but (R) is True.
Hint: Heisenberg's uncertainty principle.
Explanation:

According to Heisenberg's uncertainty principle, the exact position and exact momentum of an electron cannot be
determined simultaneously. The position of the electron and its path is not defined clearly in an atom.

Hence, the Assertion is true but the reason is false.