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प्रश्न
A convex lens has a focal length of 10 cm. At which of the following position should an object be placed so that this convex lens may act as a magnifying glass?
(a) 15 cm
(b) 7 cm
(c) 20 cm
(d) 25 cm
उत्तर
7 cm,
since the image of an object placed between the focus and the optical centre of a convex lens is enlarged and virtual.
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संबंधित प्रश्न
Study the given ray diagrams and select the correct statement from the following:
(A) Device X is a concave mirror and device Y is a convex lens, whose focal lengths are 20 cm and 25 cm respectively.
(B) Device X is a convex lens and device Y is a concave mirror, whose focal lengths are 10 cm and 25 cm respectively.
(C) Device X is a concave lens and device Y is a convex mirror, whose focal lengths are 20 cm and 25 cm respectively.
(D) Device X is a convex lens and device Y is a concave mirror, whose focal lengths are 20 cm and 25 cm respectively.
A 1 cm high object is placed at a distance of 2f from a convex lens. What is the height of the image formed?
What type of lens would you use as a magnifying glass? How close must the object be to the lens?
Describe with the help of a ray-diagram, the size, nature and position of the image formed by a convex lens when an object is placed beyond 2f in front of the lens.
If the object is moved to a point only 3 cm away from the lens, what is the new position, height and nature of the image?
The diagram alongside shows the refraction of a ray of light from sir to a liquid.
(a) write the values of (i) angle of incidence, (ii) angle of refraction.
(b) use snell’s law to find the refractive index of liquid with respect to air.
State the position of object, position of image, nature of image when: Convex lens is used as in searchlight.
An object is placed in front of a convex lens such that the image formed has the same size as that of the object. Draw a ray diagram to illustrate this.
Find the odd one out and give its explanation.
Differentiate convex lens and concave lens.
