Question

90 și 91 va rog!!!!!

Answer 1

90.

C=1/f=(n-1)(1/R₁-1/R₂)

R₁=3 m;R₂=-6 m

f=R₁R₂/[(n-1)(R₂-R₁)]=3*(-6)/[(1,5-1)(-6-3)]=-18/0,5*(-9)=2/0,5=4 m=>f=4 m

91.

C=1/f=>f=1/C=1/2=0,5 m

R₁=-R₂=|R|

C=1/f=(n-1)(1/R₁-1/R₂)=2(n-1)/|R|=>|R|=2f(n-1)

C'=(n/n'-1)(1/R₁-1/R₂)=1/f'=>f'=fn'(n-1)/(n-n')=0,5*1,75(1,5-1)/(1,5-1,75)=0,43/(-0,25)=-1,75 m=>f'=-1,75 m