Physics
Answer
Reason — For a convex lens, the first focal point is a point F1 on the principal axis of the lens such that the rays of light coming from it, after refraction through the lens, become parallel to the principal axis of the lens.
In option 2, A ray of light incident parallel to the principal axis of the lens, after refraction appears to come from the second focus F2 and not F1.
In option 3, A ray of light incident parallel to the principal axis of the lens, after refraction passes through the second focus F2 and not F1
In option 4, A ray of light directed towards the first focus F1 and not F2, emerges parallel to the principal axis after refraction.
Hence, fig 1 is correct.
Related Questions
In figure (a) and (b), F1 and F2 are the two foci of thin lenses and AB is the incident ray. Complete the diagram to show the path of the ray AB after refraction through the lens.
(a) Figure a
(b) Figure b
A ray of light parallel to the principal axis for a concave lens after refraction :
- passes through the second focus
- passes through the first focus
- appears to pass through the second focus
- appears to come from the second focus
Identify the incorrect statement :
- A real image is formed due to actual intersection of the rays refracted by the lens.
- A virtual image can be obtained on the screen.
- A virtual image is erect with respect to the object.
- A real image is inverted with respect to the object.
A ray diagram for a convex lens is shown below. In this manner, a convex lens is used in :
- camera
- cinema
- burning glass
- terrestrial telescope