1. Convex Lens:
- Draw a ray from the top of the object parallel to the principal axis; after refraction, it passes through the focal point on the opposite side.
- Draw a ray from the top of the object through the center of the lens; it continues straight without bending.
- The intersection of these two rays on the opposite side is the top of the real, inverted image.
- Measure the image height and distance from the lens.
2. Concave Lens:
- Draw a ray from the top of the object parallel to the principal axis; after refraction, it diverges as if coming from the focal point on the same side.
- Draw a ray from the top of the object toward the center of the lens; it continues straight.
- Extend the diverging refracted ray backward to intersect with the straight-through ray; this virtual intersection point is the top of the upright, virtual image.
- Measure the image height and distance from the lens (negative value).
3. Convex (i < f):
- Draw a ray from the top of the object parallel to the principal axis; after refraction, it passes through the far focal point.
- Draw a ray from the top of the object through the center of the lens; it continues straight.
- Since the object is inside the focal length, the refracted rays diverge; extend them backward to find their virtual intersection behind the object.
- This forms an upright, magnified, virtual image on the same side as the object.
- Measure the image height and distance from the lens (negative value).
4. Concave (i < |f|):
- Draw a ray from the top of the object parallel to the principal axis; after refraction, it diverges as if coming from the near focal point.
- Draw a ray from the top of the object through the center of the lens; it continues straight.
- Extend the diverging refracted ray backward to intersect with the straight-through ray; this virtual intersection is the top of the upright, reduced, virtual image.
- Measure the image height and distance from the lens (negative value).
Parent Tip: Review the logic above to help your child master the concept of concave and convex lenses worksheet.
