Please explain why the answer would be that one.
A boy holds a magnifying glass at arm’s length. He looks at a poster through the glass and sees a magnified erect image. What happens to the image if he moves the lens closer to his eyes?
A. It gets larger till it gets totally blurred at some distance.
B. It gets larger, keeping erect all the way.
C. It gets smaller and becomes totally blurred at some distance.
D. It gets smaller, keeping erect all the way.
Ans: C.
If you can capture an image of a doll on a screen using a lens, which of the following must be wrong?
A. The lens you use is a convex lens.
B. The image can be magnified.
C. The image is real.
D. The image is erect.
Ans: D
The magnification of the image is 1, and the distance between the screen and the lens is 4 cm. What is the distance between the image and the object?
A. 1cm
B. 2cm
C. 4cm
D. 8cm
Ans: D
An object is placed in front of a lens. An enlarged image is formed on the same side of the object.
a. Is the lens convex or concave? Explain your answer.
b. If the object is moved a bit closer towards the lens, how will the image change? Support your answer with a ray diagram.
Questions about lenses(f.3 level)
2008-05-26 1:42 am
回答 (2)
2008-05-27 5:12 pm
✔ 最佳答案
For the first question, with the focal length remains unchanged, the ray passing throgh the centre of lens would be steeper so the image formed would be smmaller. It may be easier for you to understand if you construct a ray diagram on your own. I guess it become blurred because there is a minimum distance for things to be seen by eyes. Not only image, you can't see some characters when they are too close to youImage captured by screen is always real. Real image is always inverted
Magnification is one means the object distance equals the image distance. The image distance is know as 4 cm stated in the question. So answer equals 2 times 4 which is 8cm
Convex lens
Only covex lens can form enlarged image
Image becomes smaller
2009-02-18 6:26 pm
Can you explain why (Q1):
If I move the lens closer to eyes
=>object distance suppose increase, image size suppose increase.
If I move the lens closer to eyes
=>object distance suppose increase, image size suppose increase.
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