Some would ignore this as a minor issue but if you are applying for a Government job, this mistake should not be a reason to delay your verification or appointment. Usually, there would be an issue if you apply for jobs wherein you are eligible on a reservation quota, as you would be needed to produce the caste certificate. Most of the Government jobs are now applied via the online mode and such errors, although minor this would be flagged up.
So, please use this opporutinty to check your other documents(Aadhaar,Voters,PAN,DL etc) for other spelling and numerical mistakes.
Once you find that everything is in order, have at least two IDs ( Aadhar or PAN) for mother to state her correct full name. Then meet a Notary who would format a name change affidavit that will have your Mother's correct name. Once, the affidavit is made, please contact two local newspaper offices (one English and one Vernacular language) and publish the corrrected name.
The draft an request letter regarding the need for name change on your 10th and 12th marks card. This would be forwarded through your school and college principal to the respective boards. There would be a small fee to be paid for the services.