Question

Seorang penderita hipermetropi dpt mmbca bku pda jarak 125cm. Agar dpt mmbaca pada jarak normal 25 cm, org trsbut hrus memakai kcmta dgn kuat lensa?

Answer 1

So = 25 cm
Si = 125cm

1/f = 1/So + 1/Si
1/f = 1/25 - 1/125 (karena bayangan yg terbentuk maya maka bertanda -)
1/f = (5-1)/125
1/f = 4/125
f = 125/4 cm = 125/4 * 1/100 = 5/16 m

P = 1/f = 1/ (5/16) = 16/5 = 3 1/5 dioptri = 3,2 dioptri