Image Formation by Lenses
Physics ⇒ Light and Optics
Image Formation by Lenses starts at 8 and continues till grade 12.
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See sample questions for grade 12
A convex lens forms an image 40 cm from the lens when the object is placed 10 cm from it. Calculate the focal length of the lens.
A convex lens has a focal length of 20 cm. An object is placed 60 cm from the lens. Calculate the magnification produced.
A lens forms a virtual, erect, and magnified image. What type of lens is it and where is the object placed?
A lens forms an image that is the same size as the object and is real and inverted. Where is the object placed relative to the lens?
A lens forms an image that is three times the size of the object and is real and inverted. What is the magnification and what does it indicate?
A student places an object 10 cm from a concave lens of focal length 15 cm. Where is the image formed?
A student uses a convex lens to focus sunlight onto a piece of paper. What does the point of brightest light on the paper represent?
An object is placed 30 cm from a convex lens of focal length 10 cm. Calculate the position of the image.
Describe the nature and position of the image formed by a concave lens when the object is placed at any position.
Explain why a concave lens cannot form a real image of an object placed in front of it.
If an object is placed at the center of curvature of a convex lens, what is the nature and size of the image formed?
If the magnification produced by a lens is -2, what does the negative sign indicate?
If the object distance (u) is negative and the image distance (v) is positive for a lens, what does this indicate about the image?
If the power of a lens is -4 D, what type of lens is it?
State the lens formula and define each term.
State two differences between real and virtual images formed by lenses.
The magnification produced by a lens is +0.5. What does this tell you about the image?
The power of a lens is +5 D. What is its focal length in centimeters?
A bi-convex lens is made of glass (refractive index 1.5) with radii of curvature of +20 cm and -20 cm. Calculate its focal length using the lens maker's formula.
A convex lens of focal length 12 cm is used to form an image twice the size of the object. Calculate the two possible object distances.
