An object is placed in front of a convex lens as shown. How does the size of its image compare with the object? A convex lens stands on a horizontal principal axis, with F₁ and 2F₁ marked on the left of the lens and F₂ and 2F₂ on the right. An upright object arrow stands exactly at 2F₁.

An object is placed in front of a convex lens as…

An object is placed in front of a convex lens as shown.

Question 24

EasyOriginal question

An object is placed in front of a convex lens as shown. How does the size of its image compare with the object?

SmallerCorrect answerYour answerThe same sizeCorrect answerYour answerLargerCorrect answerYour answerVery large, because the image forms at infinityCorrect answerYour answer

Show the answer and explanation

CorrectNot quiteAnswer B

Correct answer: B

The object is exactly at 2F₁.
An object at 2F₁ gives an image at 2F₂ that is real, inverted and the same size as the object.

Worth noting

The image forms at infinity only when the object is at F₁, not at 2F₁.

Concept: Image by a convex lens: object at 2F
Typical timeTypical: 35 s
Your timeYours: —

The rule this testsLight

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Ten questions from Everyday Physics, at your own pace.

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Ten questions from Everyday Physics, at your own pace.

An object is placed in front of a convex lens as shown.

Question 24

Explanation