Lenses

Concave lenses cause parallel light rays, such as those from an object at infinity, to diverge.

A concave lens always forms an erect and diminished virtual image.

A convex lens is used as a magnifying glass because it converges light rays to produce a magnified image.

Longsightedness, or hyperopia, occurs when light from near objects focuses behind the retina.

The principal axis is a horizontal line that passes through the center of the lens.

The optical centre of a lens is the point through which a ray of light passes without deviation.

The ciliary muscle helps to change the shape of the lens in the eye to focus on objects at varying distances.

The distance between the optical center and the principal focus of a lens is known as the focal length.

The primary function of a lens is to refract light in a specific way to form images.

A convex lens is characterized by its ability to converge light rays to a single point.

A concave lens diverges light rays, causing them to spread out.

A convex lens is thicker at the center than at the edges.

A concave lens is thinner at the center than at the edges.

The center of a lens is called the optical center.

The distance between the optical center and the principal focus is known as the focal length.

A concave lens always forms virtual images.

The cornea and lens of the eye work together to focus light, similar to a lens in a camera.

A convex lens is used to correct long-sightedness by converging light rays to focus properly on the retina.

In shortsightedness, the image is formed in front of the retina.

A concave lens is used to treat shortsightedness by diverging light rays to extend the focal length.

A telescope uses lenses to magnify distant objects.

A lens is a transparent curved piece of glass or other transparent material used to refract light.

Lenses work based on the property of refraction, which is the bending of light as it passes through different mediums.

When light passes from air to glass, it bends due to refraction.

There are two main types of lenses: convex and concave.

A convex lens is also called a converging lens because it converges light rays to a point.

A concave lens is also known as a diverging lens because it diverges light rays.

A convex lens is thick in the middle and thin at the edges.

A concave lens is curved inward, being thinner in the middle and thicker at the edges.

A convex lens can produce real images, typically when the object is placed beyond the focal point.

A concave lens produces virtual and erect images, which are always diminished.

The principal focus of a convex lens is where parallel rays of light converge after passing through the lens.

The focus of a concave lens is called virtual because the rays do not actually meet; they only appear to diverge from a point.

Focal length is the distance between the optical center of the lens and its principal focus.

The focal length of a convex lens is given a positive sign as it converges light rays.

The focal length of a concave lens is given a negative sign as it diverges light rays.

A concave lens always forms a virtual, erect, and smaller image.

After passing through a concave lens, rays diverge.

When an object is placed in front of the focal point of a concave lens, the image forms between the object and the focus.

The cornea functions similarly to a camera lens by bending light to help focus it.

In the human eye, the image is formed on the retina.

The diaphragm aperture adjusts the amount of light entering the lens in a camera.

The iris and pupil adjust the amount of light entering the human eye.

The human eye focuses on near or distant objects by changing the shape of the lens.

The ciliary muscles change the shape of the lens to help focus light onto the retina.

The retina contains photoreceptor cells that detect light.

The cornea is the first part of the eye that bends light as it enters.

Rod cells in the retina help in vision in dim light.

Rhodopsin enables night vision by helping rod cells detect low levels of light.

In bright light, rhodopsin breaks into retinal and opsin, which temporarily reduces its ability to detect light.

Deficiency in Vitamin A can cause night blindness as it is essential for the production of rhodopsin.

The retina acts like the camera film or sensor, capturing the light to form images.

The iris is most similar to the aperture of a camera, controlling the amount of light that enters.

The lens of a camera is similar in function to the cornea, as both bend light to focus it.

In a bright environment, the pupil becomes smaller to reduce the amount of light entering the eye.

A convex lens is used to correct long-sightedness by converging light rays to focus properly on the retina.

Short-sightedness is caused by the eyeball being too long, causing light to focus in front of the retina.

A person with short-sightedness has difficulty seeing distant objects clearly.

A concave lens is used to correct short-sightedness by diverging light rays to properly focus on the retina.

A magnifying glass is used to enlarge the image of an object, making it appear larger than it actually is.

A microscope uses lenses to magnify very small objects, making them visible and detailed.

Concave lenses help in correcting short-sightedness by diverging light rays so that they focus correctly on the retina.