Hệ thấu kính ghép sát

Vật lý 11.Hệ thấu kính ghép sát. Hướng dẫn chi tiết.

$f_{h ê} = \frac{f_{1} f_{2}}{f_{1} + f_{2}}; D_{h ê} = D_{1} + D_{2} k = k_{1} k_{2}$

$A B \overset{T K 1}{\to} A_{1} B_{1} \overset{T K 2}{\to} A_{2} B_{2}$

Ta có :

$\frac{1}{f_{1}} = \frac{1}{d_{1}} + \frac{1}{d_{1}'} \frac{1}{f_{2}} = \frac{1}{d_{2}} + \frac{1}{d_{2}'}$

Mà $d_{2} = a - d_{1}'$ hệ ghép sát thì $a = 0$

Cộng theo vế : $\frac{1}{f_{1}} + \frac{1}{f_{2}} = \frac{1}{d_{1}} + \frac{1}{d_{2}'} = \frac{1}{f_{h ê}}$

$A B \overset{T K 1}{\to} A_{1} B_{1} \overset{T K 2}{\to} A_{2} B_{2}$

Ta có :

$\frac{1}{f_{1}} = \frac{1}{d_{1}} + \frac{1}{d_{1}'} \frac{1}{f_{2}} = \frac{1}{d_{2}} + \frac{1}{d_{2}'}$

Mà $d_{2} = a - d_{1}'$ hệ ghép sát thì $a = 0$

Cộng theo vế : $\frac{1}{f_{1}} + \frac{1}{f_{2}} = \frac{1}{d_{1}} + \frac{1}{d_{2}'} = \frac{1}{f_{h ê}}$