<p>The best person to write your letter is the person who knows you best and can write the strongest letter. Whether it’s math or physics is not really important. You can find examples of letters that MIT considers weak, mediocre, and strong here: [MIT</a> Admissions | Info For Schools & Counselors: Writing Evaluations](<a href=“http://www.mitadmissions.org/topics/schools/writing_evaluations/index.shtml]MIT”>http://www.mitadmissions.org/topics/schools/writing_evaluations/index.shtml).</p>
<p>Often the teacher who can write the strongest letter is a teacher who has written strong letters in the past for students admitted to top schools like MIT. If you are attending a school from which no student has ever been admitted to a top-tier university, then you might consider printing up the information from the link I’ve posted and sharing it with the teacher who is willing to write a strong letter for you. It will be an eye-opener for the teacher who has never written such a letter before.</p>