Tolong ni tolong bgt yak

Suatu lensa di udara mempunyai jarak fokus 20 cm. Indeks bias kaca lensanya n = 1,5. berapa dioptri kekuatan lensanya, jika lensa berada dalam bensin? (diketahui indeks bias bensin = 1,2)

please banget kak, ksih jwbn yg bnr ya

1

Jawabanmu

Jawaban paling cerdas!
2014-03-21T16:00:22+07:00
 \frac{1}{f} =( \frac{nl}{nm} -1)( \frac{1}{R_1} + \frac{1}{R_2} )
 \frac{1}{20} =( \frac{ \frac{3}{2} }{1} -1)( \frac{1}{R_1} + \frac{1}{R_2} )
 \frac{1}{20} =( \frac{3}{2} -1)( \frac{1}{R_1} + \frac{1}{R_2} )
 \frac{1}{20} =( \frac{1}{2})( \frac{1}{R_1} + \frac{1}{R_2} )
 \frac{1}{10} =\frac{1}{R_1} + \frac{1}{R_2} ... (1)

saat dimasukkan ke bensin
 \frac{1}{f} =( \frac{ \frac{3}{2} }{ \frac{6}{5} } -1)( \frac{1}{R_1} + \frac{1}{R_2} )
 \frac{1}{f} =( \frac{15}{12} -1) \frac{1}{10}
 \frac{1}{f} =( \frac{3}{12})( \frac{1}{10} )
 \frac{1}{f} = \frac{3}{120}
 \frac{1}{f} = \frac{1}{40}
f=40 cm

P= \frac{100}{f}
P= \frac{100}{40}
P=2,5

CMIIW :3
3/2 dpt drimna kak?
infeks bias lensa 1,5
indeks bias udara 1
jadi 1,5/1 =1,5