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, 19:47: PM
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, 20:55: PM
Concept Videos
CBSE 12-science - Physics
Asked by jothisugashini216 | 16 Jul, 2024, 20:30: PM
CBSE 12-science - Physics
Asked by prithviraj.chopra2011 | 14 Jul, 2024, 23:00: PM
CBSE 12-science - Physics
Asked by basithhhabduuu | 14 Jul, 2024, 17:07: PM
CBSE 12-science - Physics
Asked by asmaabid356 | 10 Jul, 2024, 21:03: PM
CBSE 12-science - Physics
Asked by pushpamagadum21 | 09 Jul, 2024, 20:43: PM
CBSE 12-science - Physics
Asked by sumitghorband09 | 20 Jun, 2024, 21:42: PM
CBSE 12-science - Physics
Asked by axonuploadserver4 | 14 Jun, 2024, 17:41: PM
CBSE 12-science - Physics
Asked by trishaktiprasadmallik693 | 11 Jun, 2024, 07:17: AM
CBSE 12-science - Physics
Asked by rahuldevgayen4 | 10 Jun, 2024, 14:58: PM