Question

Assertion :Hydrogen atom consists of only one electron but its emission spectrum has many lines. Reason: Only Lyman series is found in the absorption spectrum of hydrogen atom whereas in the emission spectrum, all the series are found.

• 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. Both Assertion and Reason are incorrect

Answer 1

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

When the atom gets appropriate energy from outside, then this electron rises to some higher energy level. Now it can return either directly to the lower energy level or come to the lowest energy level after passing through other lower energy levels, hence all possible transitions take place in the source and many lines are seen in the spectrum.

At ordinary temperature, all atoms are present at their lowest energy level (n=1). Hence absorption transition can starts only from n=1 (and not from n=2,3,4,..). Hence only Lyman series is found in the absorption spectrum of hydrogen atom whereas in the emission spectrum, all the series are found.