Images formed by convex lenses: แบบฝึกหัด

What happens to a parallel beam of light rays after passing through a convex lens?

An object is moved slowly towards a convex lens from a very far distance until it reaches the principal focus (\(F\)). Which of the following correctly describes the change in the real image formed on a screen?

When constructing a ray diagram for a convex lens, a student draws a ray that originates from the top of the object and passes through the focal point \( F \) on the same side as the object before it hits the lens. How will this ray travel after passing through the lens?

The distance between the optical centre of a convex lens and its focal point is called the:

A convex lens has a focal length of \( 15\ \text{cm} \). If an object is placed at a distance of \( 40\ \text{cm} \) from the optical centre of the lens, what are the characteristics of the image formed?

If a student successfully projects a clear image of a candle flame onto a white wall using a single convex lens, what are the two essential characteristics of this image?

In a ray diagram for a convex lens, a light ray enters the lens parallel to the principal axis. Describe the path of this ray after it passes through the lens and explain why this occurs.

A student uses a convex lens to view a small insect. As she moves the lens closer to the insect (within the focal length), describe the change in the size and position of the virtual image observed.

A ray box is used to send light rays through a convex lens. Describe the behavior of the following three light rays:

(a) A ray that enters the lens parallel to the principal axis. (1 point)

(b) A ray that passes through the optical centre of the lens. (1 point)

(c) A ray that passes through the principal focus (\(F\)) before hitting the lens. (1 point)

A convex lens is often used in instruments like projectors and cameras because of its ability to converge light rays and form real images. Consider a convex lens with a focal length (\(f\)) of \(5\text{ cm}\).