Question

If the refracted ray from a convex lens is travelling parallel to the principal axis, then image distance is ________.

• A. equal to object distance
• B. Infinity
• C. equal to focal length of the lens
• D. equal to radius of curvature of the lens

Answer 1

Answer: (B)

Infinity

When our object is placed on the focus then the image is formed at the infinity. According to rule of refraction, any incident ray traveling through the focal point on the way to the lens will refract through the lens and travel parallel to the principal axis.