a) Theo đề bài: CV --> ∞
\(\begin{gathered}
{f_k} = \dfrac{1}{{{D_k}}} = 1m = 100cm \hfill \\
\dfrac{1}{{25}} - \dfrac{1}{{O{C_C}}} = \dfrac{1}{{100}} \Rightarrow O{C_C} = \dfrac{{100}}{3} \approx 33,3cm \hfill \\
\end{gathered} \)
b) ΔD = Dmax – Dmin =\( \dfrac{1}{OC_c} = 3dp; OC_c = \dfrac{1}{3m}\).
c) Tiêu cự kính lúp: \(d = \dfrac{1}{D} = \dfrac{25}{8} = 3,125cm.\)
Khoảng đặt vật MN xác định bởi:
\(\begin{gathered} M\xrightarrow[{{d_1};{d_1}'}]{L}M' \equiv {C_V} \hfill \\ {d_1}' \to \infty \hfill \\ {d_1} = {f_1} = 3,125cm \hfill \\ \end{gathered} \)
|
\(\begin{gathered} N\xrightarrow[{{d_2};{d_2}'}]{L}N' \equiv {C_C} \hfill \\ {d_2}' = - \left( {\dfrac{{100}}{3} - 30} \right) = - \dfrac{{10}}{3}cm \hfill \\ \dfrac{1}{{{d_2}}} = \dfrac{8}{{25}} + \dfrac{3}{{10}} = \dfrac{{31}}{{50}} \hfill \\ {d_2} \approx 1,613cm \hfill \\ \end{gathered} \)
|
Khoảng đặt vật: 16,13mm ≤ d ≤ 31,25mm.
Số bội giác khi ngắm chừng ở vô cực:
\({G_\infty } = \dfrac{{O{C_C}}}{{{f_1}}} \approx 10,67\)