What happens to a path of a light ray parallel to the principal axis, after it passes through a converging lens?

It passes through the focal point, on the princial axis, on the other side.

When a light ray parallel to the principal axis passes through a converging lens, its path undergoes several changes. Let's go through the step-by-step process:

1. The parallel light ray initially enters the lens and is refracted towards the normal (a line perpendicular to the lens surface) at the first surface of the lens. This refraction occurs because light travels at a different speed in the lens material compared to the surrounding medium (usually air).

2. As the ray continues to pass through the lens, it reaches the center or optical axis of the lens. At this point, it does not deviate and continues to go straight through without any refraction because the angle of the ray is now perpendicular to the lens surface.

3. Finally, when the ray hits the second surface of the lens, it again undergoes refraction away from the normal. The angle of refraction depends on the shape and curvature of the lens. In the case of a converging lens, the ray will be refracted towards the principal axis.

4. The refracted ray converges towards a point on the principal axis called the focal point (F). The distance between the lens and the focal point is called the focal length (f) of the lens. This focal point is on the opposite side of the lens from where the initial parallel ray entered.

In summary, when a light ray parallel to the principal axis passes through a converging lens, it is refracted towards the normal at the first lens surface, continues straight through without deviation, and then refracted towards the principal axis at the second lens surface, ultimately converging towards a focal point on the opposite side of the lens.

When a light ray is parallel to the principal axis and passes through a converging lens (also known as a convex lens), it undergoes refraction and its path changes. Here's an explanation of what happens:

1. Refraction at the lens surface: As the parallel light ray encounters the surface of the converging lens, it bends (or refracts) towards the normal (a line perpendicular to the surface). This refraction occurs because the speed of light is different in different media, and a change in speed causes the ray to change direction.

2. Focusing effect: After the refraction at the first surface, the light ray continues to travel through the lens material. Due to the shape of the converging lens (thicker in the center and thinner at the edges), the light ray refracts again towards the principal axis as it enters the thicker part of the lens. This refraction causes the light ray to converge towards a single point in space, known as the focal point.

3. Converged path: Once the light ray has passed through the converging lens, it will converge and intersect with the principal axis at a specific point. This point is known as the focal point (F).

The path of the light ray, after passing through the converging lens, is focused towards a single point, forming an image. If an object is placed at infinity (very far away from the lens), the image formed by the converging lens will be a sharp point of light at the focal point. If the object is placed between the lens and its focal point, a magnified and inverted image will be formed on the opposite side of the lens.

It's important to note that the exact position and characteristics of the image formed by a converging lens depend on the lens's focal length and the position of the object relative to the lens. The mathematical equations of lens optics can be used to calculate more precise values and characteristics of the formed image.