Question

Benda tingginya 5 cm berada didepan cermin cekung sejauh 8 cm. jika jari-jari cermin 20 cm, berapa:
a. jarak fokus
b. tinggi bayangan

Answer 1

A. f = 1/2 x r
      = 1/2 x 20
      = 10

b. 1/f = 1/s + 1/s'
    1/10 = 1/8 + 1/s'
   1/s' = 1/8 - 1/10
         = 5/40 - 4/40
         = 1/40
    s' = 40
   s'/s = h'/h
   40/8 = h'/5
     5=h'/5
    h' = 25