Question

Assertion :$\Psi$ indicates the amplitude of electron - wave. Reason: ${\Psi }^2$ denotes the probability of finding an electron in the space around the nucleus.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
• C. Assertion is correct but Reason is incorrect
• D. Assertion is incorrect but Reason is correct

Answer 1

The correct option is B Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion

$\Psi$ is wave function of electron. The wave function may be regarded as the amplitude function expressed in terms of coordinates $x,y$ and $z$. This wave function may have positive or negative values depending upon the values of coordinates.

When Schrodinger equation is solved, it is observed that for some region the values of $\Psi$ is negative and for other regions the value of $\Psi$ is positive. But the probability must be always positive and cannot be negative. It is therefore proper to use ${\Psi }^2$ in favour of $\Psi$.
${\Psi }^2$ is a probability factor which describes the probability of finding the electron within a small space.