When an object is placed within the focal length of a convex lens, the image appears on the same side as the object itself. This situation is shown below. In this situation, which of the following statements is true?

Lens and candle

A. si and di are both expressed as negative values, f as a positive value

B. si and di are both expressed as positive values, f as a negative value

C. si, di, and f are all expressed as negative values.

D. si, di, and f are all expressed as positive values.

A

si, di, are expressed as negative and f is expressed as positive values.

Explanation:

When the object is located at a location in front of the focal point of a convex len, the image will always be located somewhere on the same side of the lens as the object. The image is located behind the object. In this case, the image will be an upright image and the image is enlarged

In this question, the relationship between the focal length, image distance di and object distance is

I/f = 1/di + 1/do that is

I/f - 1/di - 1/do = 0

The image size si is also negative since the image is a virtual image.

Therefore, si, di, are expressed as negative, f is expressed as positive values.

f=ma newton

f=100x2.5=250n