194.
Ta có:
\(\begin{array}{l}
{i_1} = \dfrac{{\lambda D}}{a}\\
{i_2} = \dfrac{{\lambda \left( {D + 0,2} \right)}}{a}\\
\Rightarrow \dfrac{1}{{1,2}} = \dfrac{D}{{D + 0,2}} \Rightarrow D = 1m\\
\Rightarrow a = 0,6mm
\end{array}\)
195.
Ta có:
\(\dfrac{\lambda }{2} = \dfrac{L}{6} = \dfrac{3}{6} = 0,5 \Rightarrow \lambda = 1cm\)
Tốc độ truyền sóng là:
\(v = \lambda f = 0,01.20 = 0,2m/s = 20cm/s\)
196.
Ta có:
\(\begin{array}{l}
{d_2} - {d_1} = 4\lambda = 4.\dfrac{v}{f}\\
\Rightarrow 20 - 16 = 4.\dfrac{v}{{20}}\\
\Rightarrow v = 20m/s
\end{array}\)
197.
Ta có:
\(\begin{array}{l}
{d_2} - {d_1} = \lambda = \dfrac{v}{f}\\
\Rightarrow 21 - 19 = \dfrac{v}{{13}}\\
\Rightarrow v = 26m/s
\end{array}\)
