Copyright law states that copyright is not infringed in any material used for the purposes of examination, i.e. in setting the questions, communicating the questions to the candidates, or in answering the questions, as long as the use is accompanied by a sufficient acknowledge where it is possible to do so and the use is in line with fair dealing - i.e. the amount used is no more than necessary for the purpose, the use is not negative or derogatory, the use does not impact on commercial sales.
This means you can use any material at all for examination purposes without having to seek permission from the copyright holder or find alternatives that are already free to use, and you can make as many copies as you need to - as long as your use is fair and referenced.
The only exception to this is for printed music - you cannot make a copy of printed sheet music for the purposes of an exam, even if it is a piece you are required to play.
It is generally accepted that the examination exception in copyright law also applies to assessed work, i.e. any piece of work that will be assessed and count towards your final grade. This means you can copy, show, perform or play any amount of anything without needing to seek permission, as long as it is part of this assessed work.
Whilst it is not always possible to include references or acknowledgements in a written exam piece, you must always do so in assessed work. If your work is visual, audio or film, you must include a separate written sheet listing the sources of material you have used.
Your use must also comply with 'fair dealing' - there is no firm definition of fair dealing but it includes issues such as the amount used, the way the material is handled (i.e. being used in a negative, demeaning or prejudicial way), whether the use will impact on commercial sales.
However, this exception applies solely to the assessed or examined work. If your work is intended to go on wider display, i.e. beyond yourself and the assessor(s), you must ensure you have permission for the material used or use pre-cleared material. So if your assessed work includes a public performance or if your poster or graphic work will be included in an End of Year Show, you must ensure you have cleared any copyrighted material for use.
If the assessed work includes the creation of a web page, this cannot be made available to anyone but the assessor. If it is made available on the internet, all material used must be pre-cleared or used with permission.