Question

A convex lens is a transparent instrument that uses refraction to bend and focus light from an object, forming a sharp image. We'll first investigate how the lens produces an image from a point source of light (a lamp).

Select Screen at upper right, which makes the object a lamp and gives a black screen that can be dragged around.

Select Many rays at upper left to see how the lens bends some of the rays of light from the lamp.

With the lamp positioned far to the left of the lens, you should see that the rays that go through the lens converge to a point. If the screen is placed where the beams converge, the image on the screen will be in focus (it will be a small dot of light since that is what the object looks like in this case). The screen is then at the focal plane. As the lamp is moved closer to the lens, the distance between the focal plane and the lens _____.

A convex lens is a transparent instrument that uses refraction to bend and focus light from an object, forming a sharp image. We'll first investigate how the lens produces an image from a point source of light (a lamp).

Select Screen at upper right, which makes the object a lamp and gives a black screen that can be dragged around.

Select Many rays at upper left to see how the lens bends some of the rays of light from the lamp.

With the lamp positioned far to the left of the lens, you should see that the rays that go through the lens converge to a point. If the screen is placed where the beams converge, the image on the screen will be in focus (it will be a small dot of light since that is what the object looks like in this case). The screen is then at the focal plane. As the lamp is moved closer to the lens, the distance between the focal plane and the lens _____.

	increases.
	decreases.
	remains the same.

Answer 1

When the lamp is kept closer to the lens, the rays diverge more quickly when compared to the diverging when the lamp is kept far way. As these rays after going through the lens takes longer time to converge the distance between the focal lens and lens increase. Therefore, the correct option is increases.