Lenses
Physics ⇒ Light and Optics
Lenses starts at 8 and continues till grade 12.
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See sample questions for grade 8
A convex lens has a focal length of 20 cm. What is its power?
A lens forms an image that is smaller than the object. What can you say about the position of the object?
A lens has a power of -2 diopters. Is it a convex or concave lens?
A student observes that the image formed by a lens is virtual, erect, and larger than the object. Which lens is being used and where is the object placed?
A student places an object 30 cm from a convex lens of focal length 15 cm. Where will the image be formed?
If a lens forms an image at the same distance as the object but on the opposite side, what is the nature of the lens?
If an object is placed at the focus of a convex lens, what type of image is formed?
If the focal length of a lens is 10 cm, what is its power in diopters?
If the object distance (u) is -20 cm and the image distance (v) is +30 cm, what is the focal length (f) of the lens?
What happens to the focal length of a lens if it is placed in water instead of air?
What is meant by the term 'virtual image'?
What is the effect of increasing the curvature of a lens surface on its focal length?
What is the focal length of a lens?
What is the formula for the power of a lens in terms of its focal length?
What is the principal axis of a lens?
What is the sign convention for the focal length of a convex lens?
What is the unit of power of a lens?
What type of image is formed by a concave lens for a real object?
Which lens is used in a simple microscope?
Which type of lens is used in a camera to focus light onto the film or sensor?
