The principal axis of a convex lens is along x-axis.The coordinates of a point object and its image are (-20cm,2cm) and (25cm,-4cm) respectively. Its focal length is-. 15cm. 30cm. 5cm. 10cm
Answers
lens formula
The formula gives the relationship between object distance(u), image distance(v) and the focal length(f). The lens formula is expressed as,
1/f= 1/v - 1/u
the lens formula is valid in all situations in the case of any spherical lens.
Here object distance u=-20cm
image distance v = 25cm
focal length of lens = f
we have 1/f= 1/v - 1/u
from this equation we get
f =(uv)/(u-v) = (-20 x 25)/(-20 -(-25)) ≈ 10cm
Therefore focal length is 10cm
Focal length: The distance between the center of a lens and its focus is called the focal length.
Given:
X axis coordinate of the object (-20cm, 2cm)
X axis coordinate of the image (25cm, -4cm)
Solution:
According to lens formula,
1 / f = 1 / v - 1 / u
The distance of object distance u = -20 cm
The distance of image distance v = 25 cm
The focal length,
f = ( u v ) / ( u - v )
f = ( - 20 x 25 ) / ( -20 - ( -25 ) )
f ≅ 10cm
Hence, the focal length is 10cm.
Read more on Brainly.in - https://brainly.in/question/6430826