A long sighted person cannot see objects clearly at a distance less than 40cm from his eyes. The power of the lens needed by him to read a paper at 25cm is --------?

Asked by Rajeev Kumar | 19th Nov, 2010, 09:36: PM

Expert Answer:

Dear student,
1/f = 1/do + 1/di
 
do= 25, di = -40
1/f = 1/25 + 1/(-40)
 
1/f = 0.01 = f = 100 cm
Power = 1/1m = +1.0 D ( converging lens)
 
Hope this helps.
 
Thanking you
Team
Topperelarning.com

Answered by  | 24th Nov, 2010, 01:16: PM

Queries asked on Sunday & after 7pm from Monday to Saturday will be answered after 12pm the next working day.