Question

URGENT !!! DAU FUNDA !!!!Distanta focala a unei lentile subtiri, plan-concave , cu raza de curbura de 10 cm si indicele de refractie egal cu 3/2 , este : a)-2m b)-20cm c)-0,5 m d)-50cm

Answer 1

Răspuns:

R1<0 (lentila divergenta), raspuns b

Answer 2

C=1/f=(n-1)(1/R₁-1/R₂)

R₁=-|R|;R₂->∞

1/f=-(n-1)/|R|=>f=-|R|/(n-1)=-10/(3/2-1)=-10/0,5=-20 cm