What is the nature of the image formed in a concave lens?

An object is placed 12cm away from a convex lens whose focal length is 10cm. What will the nature of the image formed? 

Combining red and green light (with equal intensity) makes ________ light; combining red and blue light (with equal intensity) makes _______ light; and combining blue and green light (with equal intensity) makes _______ light. Choose the three colors in respective order.

Which of the following describes the best, what will happen to a light ray incident on an air- to- glass - boundary?

What happens when complementary colors are mixed together in equal amounts?

Through which part of the lens the ray of light without suffering deviation and in which position is the object placed if a convex lens always gives real image? 

An object is placed at a distance of 30.0cm from a thin converging lens a long its axis.  The lens has a focal length of 10.0cm. What are the values of the image distance and magnification (respectively)? 

Identify correct combination of the visual problem and the lens that can be used to cure it.

Which of the following describes  the best image for a thin converging lens that forms whenever the object is  at a distance less than the focal length from the lens? 

Sunsets often have a reddish- orange color associated with them.  Which phenomenon does the attribute?