Which of these statements are incorrect, and what are they supposed to be?I'm finding the topic "focusing devices" under "Light" rather a struggle, as we did not go through it much at school, and...

Which of these statements are incorrect, and what are they supposed to be?

I'm finding the topic "focusing devices" under "Light" rather a struggle, as we did not go through it much at school, and I'm studying for my exams-

a) Real images formed by convex lenses are always bigger than the original object.

b) Virtual images formed by convex lenses are always bigger than the original object.

c) Concave lenses can form only virtual images.

d) Images in a concave lens are always the right way up.

e) Real images in a concave lens are always the right way up.

and it'd be great if you could explain the following in simple terms! Thanks :)

Focal Length / Principal Axis / Myopic / Hyperopic

 

 

 

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william1941 | College Teacher | (Level 3) Valedictorian

Posted on

Option one, real images formed by convex lenses are always bigger than the original object, is incorrect. This is true only if the object is kept at a distance between the focal length and twice the focal length.

The focal length is defined as distance between the focus and the point at which the normal drawn from the focus strikes the lens.

The principle axis is the line normal to the mirror and passing through the focus.

Myopic and Hyperopic are used with relation to a problem of the eye when the eye lens is unable to focus light on the retina. In Myopia the rays of light are focused in front of the retina and in hyperopic the rays of light are focused behind the retina. They are also called nearsightedness and farsightedness resp.

 

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