For transverse electric waves between parallel plates, the lowest value of m, without making all the field components zero, is equal to

A. Waveguide match B. Cavity match C. Direct coax-helix match D. All of the above

A. A long time constant B. Low-pass filters C. The shortest possible time D. The restricted high-frequency response

A. $${\text{S}} = \frac{{2\lambda {\text{R}}}}{{\text{L}}}$$ B. $${\text{S}} = \frac{{3\lambda {\text{R}}}}{{\text{L}}}$$ C. $${\text{S}} = \frac{{\lambda {\text{R}}}}{{\text{L}}}$$ D. $${\text{S}} = \frac{{\text{L}}}{{\lambda {\text{R}}}}$$

A. To focus the beam of primary electrons B. To shield the electron beam from unidirectional magnetic C. As a second anode and to prevent the build-up of secondary field D. All of these