An object is placed between infinity and the pole (P) of a convex mirror. The position of the image is
- A.between pole (P) and the focus (F), behind the mirror
- B.between the focus (F) and infinity, behind the mirror
- C.between the pole (P) and the infinity, in front of the mirror
- D.at the focus (F), behind the mirror
Correct answer
Explanation
The correct answer is A, between pole (P) and the focus (F), behind the mirror. For any position of a real object in front of a convex mirror, the image forms behind the mirror between P and F.
A convex mirror bulges outward, and its focus and centre of curvature lie behind it. Rays from an object diverge after reflection, and only their backward extensions meet, so the image is always virtual, erect and smaller than the object. As the object moves from near the pole out towards infinity, the image moves from just behind P towards F; only when the object is at infinity does a highly diminished, point-sized image form at F itself. Because it always gives a small, upright image of a wide area, the convex mirror is used as a rear-view mirror in vehicles and at blind turns.
B is wrong because the image never forms beyond F behind a convex mirror. C is wrong because a convex mirror cannot form a real image in front of it. D is wrong because the image is at F only when the object is at infinity, not between infinity and P.
Exam tip: convex mirror: image always virtual, erect, diminished, between P and F; at F only for an object at infinity.
Practice Questions
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- A.higher concentration to its lower concentration through a cell wall.
- B.lower concentration to its higher concentration through a fully permeable membrane.
- C.higher concentration to its lower concentration through a fully permeable membrane.
- D.higher concentration to its lower concentration through a semi-permeable membrane.
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Osmosis is the passage of water from where water is more concentrated (a dilute solution) to where it is less concentrated, across a membrane that lets water through but holds back solutes.
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- A.diamagnetic property
- B.paramagnetic property
- C.ferromagnetic property
- D.electromagnetic property
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Read the full explanation →The chemical properties of an element depend upon
- A.the number of isotopes of the element
- B.the mass number of the element
- C.the total number of neutrons in the element
- D.the number of electrons in the outermost shell of the element
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Read the full explanation →Which one of the following is not found in animal cells ?
- A.Free ribosomes
- B.Mitochondria
- C.Nucleolus
- D.Cell wall
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Read the full explanation →A student was doing an experiment on increasing the cell division among plants. She asked her supervisor to suggest the specific plant hormone for the same. Had you been her supervisor, which plant hormone would you suggest?
- A.Abscisic acid
- B.Gibberellins
- C.Cytokinin
- D.Auxin
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Cytokinins are the plant hormones whose main job is to promote cell division, or cytokinesis, which gives them their name.
Read the full explanation →