The General Teaching Council for England heard that Tina Byrom had given her music AS-level students the answer to a question on Bach's Chorales.
Ms Byrom, who began teaching at Billborough College, Nottingham, in 1999, was also accused of not preparing students adequately for the exam, encouraging them to copy answers from each other and then falsely signing exam scripts saying that they contained the students' own work.
The re-convened GTCE hearing on Monday threw out the first three allegations but said it was satisfied that she had signed the exam papers without checking their content.
The case centred around a compositional techniques exam, which required students to complete a pre-released script of the initial chords of a chorale.
The papers were submitted in May 2001, but the exam board Edexcel claimed there were similarities between scripts. Jo Joynes, an independent consultant who investigated the case, told an earlier hearing that students had complained of having only one lesson on the Chorales in which they were told to copy an answer from the board.
David Sibley, also a music teacher at the college, said that Ms Byrom had asked him for a rough working of an answer to the exam question, and he had later recognised some of the students' work as his own.
Ms Byrom, who denied the charges, told the hearing that most pupils missed the deadline for submitting work and that she had not had enough time to check them before they were sent to the exam board.
She added that some pupils had been absent from important lessons, and it was normal for them to catch up using each other's work.
Ms Byrom denied that she had used rough working from Mr Sibley, claiming that he had not given it to her until after she had completed the lesson addressing the exam question.
Ms Byrom also received a reprimand which will stay on the GTCE register for two years.