Draw a ray diagram of formation of images by the convex lens when object placed between 1.Infinity, 2. beyond 2F1

Explanation

(i)Ray diagram for object placed between F and 2F

(ii)`[OH^-]=1xx10^(-11)` m
`pOH=-log_10[OH^-]=-log_10 [10^(-11)]`
`=-[-11xxlog_10 10]`
=-(-11)=11
pH+pOH =14
pH=14-pOH
pH=14-11=3