Lenses
Physics ⇒ Light and Optics
Lenses starts at 8 and continues till grade 12.
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See sample questions for grade 11
A lens forms an image 20 cm from the lens when the object is placed 10 cm from it. What is the focal length of the lens?
A lens forms an image that is virtual, erect, and larger than the object. Which type of lens and object position is this?
A lens has a focal length of 25 cm. What is its power in diopters?
A lens has a power of +5 D. What is its focal length in centimeters?
A person with hypermetropia uses which type of lens in their spectacles?
A ray of light passes through the optical center of a thin lens. What happens to its path?
A student uses a convex lens to focus sunlight onto a piece of paper. What property of the lens is being demonstrated?
Calculate the image distance if an object is placed 30 cm from a convex lens of focal length 10 cm.
Describe the nature and position of the image formed by a convex lens when the object is placed at infinity.
Explain why a convex lens can be used as a magnifying glass but a concave lens cannot.
If a lens forms an image that is the same size as the object and inverted, where is the object placed?
If an object is placed at 2f from a convex lens, where will the image be formed?
If the object distance is negative in the lens formula, what does it indicate about the object's position?
If the power of a lens is -2 D, what type of lens is it?
State the lens formula relating object distance (u), image distance (v), and focal length (f).
The refractive index of the lens material increases. What happens to the focal length of the lens?
