Explanation

Long-sightedness is also known as hyperopia.

It is a vision defect where the image is formed beyond the retina, rather than directly on it.

This occurs when the eyeball is too short or the cornea is too flat, causing light to focus at a point behind the retina.

As a result, close objects appear blurry, while distant objects may remain clear.

Explanation

A magnifying glass is also known as a simple microscope.

Because it magnifies objects, making them appear larger than they actually are.

It is called "simple" because it consists of a single lens.

Explanation

In an optical fiber, the core is made of a material with a relatively high refractive index, typically glass or plastic with a high refractive index.

This allows the light to be confined and transmitted through the fiber via total internal reflection.

The cladding surrounding the core has a lower refractive index, which helps to keep the light within the core.

Explanation

Total internal reflection occurs when a light wave reaches the boundary between a denser medium and a rarer medium.

All of the light is reflected back into the denser medium.

Explanation

• A magnifying glass, also known as a convex lens.
• It forms an enlarged virtual image that is upright.

The image formed by a magnifying glass:

• Image type: Virtual
• Orientation: Upright
• Size: Enlarged

Explanation

The human eye acts like a Camera, capturing light and focusing it onto the retina to form an image.

The eye's lens, aperture, and retina work together to create a visual representation of the world, similar to a camera's mechanism.

Explanation

Telescopes are designed to collect and magnify light from distant objects, such as stars, planets, and galaxies.

They are ideal for viewing faint or dim objects in the night sky, as they can gather more light than the human eye alone.

Explanation

The critical angle is the angle of incidence above which total internal reflection occurs.

It can be calculated using Snell's law:

n1 sin(θ1) = n2 sin(θ2)

where n1 = 1.33 (refractive index of water), θ1 = critical angle, n2 = 1 (refractive index of air), and θ2 = 90° (angle of refraction).

Rearranging the equation to solve for θ1, we get:

θ1 = arcsin(n2 / n1)

Substituting the values, we get:

θ1 = arcsin(1 / 1.33) ≈ 48.8°

So, the critical angle is approximately 48.8°.

Explanation

The eyepiece lens has a shorter focal length compared to the objective lens.

It typically around 1-2 cm.

Explanation

• When a light ray enters from a denser medium to a rarer medium, it bends away from the normal (a line perpendicular to the surface).

Key Points:

• Denser to rarer: Away from normal
• Rarer to denser: Toward normal