Lenses
Physics ⇒ Light and Optics
Lenses starts at 8 and continues till grade 12.
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See sample questions for grade 9
A lens has a power of -2 D. What type of lens is it?
Describe the difference between a real and a virtual image.
If an object is placed at 2F in front of a convex lens, where will the image be formed?
State one use of a concave lens in daily life.
A convex lens has a focal length of 10 cm. An object is placed 30 cm from the lens. Calculate the image distance.
A lens forms an image that is three times the size of the object and is real. What is the magnification?
A lens forms an image that is virtual, erect, and smaller than the object. What type of lens is it?
A student places an object 5 cm from a convex lens of focal length 10 cm. What type of image is formed?
A concave lens always forms an image that is:
(1) Real, inverted, and diminished
(2) Virtual, erect, and diminished
(3) Real, erect, and magnified
(4) Virtual, inverted, and magnified
Which lens is used as a magnifying glass?
(1) Concave lens
(2) Convex lens
(3) Cylindrical lens
(4) Plano-concave lens
Which of the following best describes the image formed by a convex lens when the object is at infinity?
(1) Real, inverted, highly diminished, at focus
(2) Virtual, erect, highly magnified, at focus
(3) Real, erect, same size, at 2F
(4) Virtual, inverted, diminished, at 2F
Which of the following is a converging lens?
(1) Concave lens
(2) Convex lens
(3) Plano-concave lens
(4) Biconcave lens
A convex lens forms a virtual image when the object is placed ________ the focal length.
A lens that is thicker at the center than at the edges is called a ________ lens.
Fill in the blank: The power of a lens is measured in ________.
The distance between the optical center and the principal focus of a lens is called the ________.
True or False: A concave lens always forms a virtual image.
True or False: The image formed by a concave lens is always on the same side of the lens as the object.
True or False: The image formed by a convex lens can be smaller, larger, or the same size as the object depending on the object's position.
True or False: The image formed by a convex lens is always real.
