Request a call back

Join NOW to get access to exclusive study material for best results

CBSE Class 12-science Answered

The focal length of convex lens 20 cm. It is kept in contact with a concave lens of focal length 25cm. Determine the focal length and power of the combined lens.
Asked by imranbharveli | 07 Mar, 2020, 07:47: PM
answered-by-expert Expert Answer
Let f1 be the focal length of convex lens and f2 be the focal length of concave lens.
 
If F is focal length of comined lenses, then we have, 1/F = ( 1/f1 ) + ( 1/f2 )
 
1/F = (1/20) - (1/25) = 1/100
 
hence focal length F of combined lenses is 100 cm
 
power of convex lens P1= 1/0.2 = +5
power of concave lens P2= 1/(-0.25) = - 4
 
power of combined lens = P1 + P2 = +5 -4 = +1
Answered by Thiyagarajan K | 07 Mar, 2020, 08:55: PM
CBSE 12-science - Physics
Asked by mailtoanjalip2005 | 16 Mar, 2024, 08:22: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
Asked by am1954077 | 08 Mar, 2024, 04:57: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
Asked by himanshurawat5823 | 08 Mar, 2024, 01:24: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
Asked by rohandhawaniya17112006 | 06 Mar, 2024, 03:32: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
Asked by shivamtkr7767 | 03 Mar, 2024, 12:45: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
Asked by sahupranav2006 | 02 Mar, 2024, 03:37: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
Asked by rishabhverma895334 | 01 Mar, 2024, 07:24: AM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
Asked by writetoakashyadav | 28 Feb, 2024, 07:41: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
Asked by nikstar1456 | 14 Feb, 2024, 01:09: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
Get Latest Study Material for Academic year 24-25 Click here
×