Correct Answer - Option 3 : a
Concept:
The cutoff frequency is given as:
\({f_c} = \frac{c}{2}\sqrt {{{\left( {\frac{m}{a}} \right)}^2} + {{\left( {\frac{n}{b}} \right)}^2}} \)
The cutoff wavelength of a waveguide is given by:
\({{\rm{λ }}_{\rm{c}}} = \frac{2}{{\sqrt {{{\left( {\frac{{\rm{m}}}{{\rm{a}}}} \right)}^2} + {{\left( {\frac{{\rm{n}}}{{\rm{b}}}} \right)}^2}} }}\)
Analysis:
Put m = 2 and n = 0
then we will get λ
c = a
