Question
According to the ray diagram rule for lenses, a ray appearing to travel towards the principal focus of a concave lens will, after refraction,
emerge parallel to the principal axis
converge to a real point beyond the lens
reverse direction entirely
bend at 90 degrees to the axis
Detailed Explanation
The chapter states that a ray appearing to meet at the principal focus of a concave lens, after refraction, emerges parallel to the principal axis.