1. The problem statement, all variables and given/known data Q. A cylindrical cavity resonator has diameter of 24 mm and length 20 mm. The dominant mode and the lowest frequency band are operated as ? I am providing a picture of problem to show the options given to me. I solved the problem by calculating resonant frequency for cavity resonator and my answer is coming to be (a). But on considering the condition " TM110 mode is dominant where 2a > d , and that the TE111 mode is dominant when d > 2a. My answer is coming to be (d). Then which one should I consider of two options. 2. Relevant equations 3. The attempt at a solution I am providing pictures of my work below.