Physics Chapter 14.7: Double Convex Lenses

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Questions and Answers

What characteristics does an image have when an object is placed outside 2F of a convex lens?

Inverted, diminished, and real (correct)

Inverted, enlarged, and virtual

Upright, diminished, and real

Upright, enlarged, and virtual

Which of the following describes the lens equation?

1/do + 1/di = 1/f (correct)

f = do + di

1/do - 1/di = 1/f

do - di = f

How would a convex lens be used to create a magnifying effect?

By placing the object beyond 2F

By placing the object at F

By using a concave lens instead

By placing the object inside F (correct)

What is the result of placing an object between F and 2F in front of a convex lens?

The image appears beyond 2F, is real, and enlarged Signup and view all the answers

Where must an object be placed to produce a virtual image with a convex lens?

Inside the focal length (F) Signup and view all the answers

Which of the following is true regarding double convex lenses?

They have focal points located on both sides of the lens Signup and view all the answers

What happens when an object is placed at F in front of a convex lens?

The image becomes virtual and enlarged on the same side Signup and view all the answers

What is a necessary condition for a convex lens to form a real image?

The object must be placed outside 2F Signup and view all the answers

What characteristic defines a convex lens?

Has focal points on both sides Signup and view all the answers

In a refracting telescope, what occurs to light rays that are parallel when they pass through a convex lens?

They converge at the focal point. Signup and view all the answers

What happens to the image when the object is located between F and 2F for a double convex lens?

The image is real and inverted. Signup and view all the answers

Which equation is relevant when dealing with lenses?

Lens Equation Signup and view all the answers

At what point does Ray 1 travel before being refracted by a convex lens?

Parallel to the principal axis Signup and view all the answers

What type of image is formed on a screen in front of a double convex lens when the object is beyond 2F?

Real and diminished Signup and view all the answers

What is the distance that refers to '2F' in lens terminology?

Twice the focal length of the lens Signup and view all the answers

Which of the following optical devices does NOT typically use a convex lens?

Concave mirror Signup and view all the answers

What type of image is formed when an object is placed between 2F and F with a convex lens?

Real, inverted, and enlarged Signup and view all the answers

What happens to the image when an object is placed inside the focal length (F) of a convex lens?

The image is virtual, upright, and enlarged Signup and view all the answers

In the ray diagram for a convex lens, what does the ray that approaches the lens parallel to the principal axis do?

Refracts through the focal point Signup and view all the answers

What is the image position when the eye is placed beyond the object visible in a convex lens?

At a position beyond 2F Signup and view all the answers

When solving for image distance (di) using the lens formula, what significance does a positive value indicate?

The image is real and inverted Signup and view all the answers

Given an object height of 1.00 cm and object distance of 8.00 cm, what is the image height if the image distance is calculated to be 24.0 cm?

3.00 cm Signup and view all the answers

Which material characteristic must a lens have to properly refract light?

An index of refraction greater than that of air Signup and view all the answers

When using the lens formula, what is the known relationship between the object distance (do), image distance (di), and focal length (f) expressed?

(1/do) + (1/di) = (1/f) Signup and view all the answers

Study Notes

Refracting Telescopes and Lenses

Refracting telescopes utilize double convex lenses to focus images, with notable examples being found at the Lick Observatory in San Jose, California.
Lenses are usually made from transparent materials like glass or plastic, having a higher index of refraction than air.
A convex lens is identified as thicker in the center compared to the edges and is used in various optical devices, including eyeglasses, microscopes, and cameras.

Characteristics of Double Convex Lenses

Double convex lenses possess two focal points, one on each side, and important reference points located at twice the focal length (2F).
Light rays entering the lens parallel to the principal axis refract through the focal point on the opposite side, while those passing through the focal point exit parallel to the principal axis.

Image Formation by Convex Lenses

When the object is placed outside of 2F, the image appears between F and 2F on the other side, appearing inverted, diminished, and real.
For objects between 2F and F, the resulting image is beyond 2F, real, inverted, and enlarged.
If an object is positioned within the focal length (inside F), the image is on the same side as the object, appearing virtual, upright, and enlarged.

Ray Diagrams

To locate the images with lenses, only two rays are needed: one parallel to the principal axis and another passing through the focal point.
The convergence of the refracted rays on the opposite side forms the image.

Example Calculations

Applying the lens equation (1/do) + (1/di) = (1/f) allows for solving image distances and heights.
If an object is placed 40.0 cm from a lens with a +8.00 cm focal length, the image distance calculated would be 10.0 cm.
For an object height of 1.00 cm positioned 8.00 cm from a lens with a 6.00 cm focal length, image calculations result in a height of 3.00 cm, three times the original.

Virtual and Real Images

A real image can be projected on a screen, while a virtual image cannot be projected and appears upright.
The ray tracing technique visually demonstrates how images form and can help perceive the nature of the image based on the object's position relative to the lens.

Lens Applications

Convex lenses are fundamental for magnification, as seen in magnifying glasses, where they create larger images of closer objects.
Understanding lens behavior is crucial for their applications in optics and various imaging technologies.

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Description

This quiz covers the concepts related to double convex lenses and their applications in refracting telescopes, highlighting the notable telescope at the Lick Observatory. Test your understanding of how lenses focus images and the significance of these optical devices in astronomical observations.