(a) An object is placed well outside the principal focus of a convex lens. Draw a ray diagram to show how the image is formed, and say whether the image is real or virtual.(b) What is the effect on the size and position of the image of moving the object (i) towards the lens, and (ii) away from the lens?
(a) When an object is placed well outside the principal focus of a convex lens, the image formed is real and inverted as shown in the figure.
(b) The effect on the size and position of the image:
(i) If an object is moved towards the lens , then the position of the image starts moving away from the lens, towards infinity (on the right side of the lens), and the image size will keep on increasing till the object reaches focus.
After that, when the object is moved closer to the lens, the image is formed behind the object (left side of the lens). This image is virtual, erect, and magnified in size.
(ii) If an object is moved away from the lens, the image size will keep on decreasing and the image keeps on shifting towards the lens.
Related Articles If an object is placed at the focus of a convex lens, where is the image formed?
The distance between an object and a convex lens is changing. It is noticed that the size of the image formed on a screen is decreasing. Is the object moving in a direction towards the lens or away from it?
Draw a ray diagram to show the formation of a real magnified image by a convex lens. (In your sketch the position of object and image with respect to the principal focus of lens should be shown clearly).
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.
An image formed by a lens is erect. Such an image could be formed by a$(a)$. convex lens provided the image is smaller than object.$(b)$. concave lens provided the image is smaller than object.$(c)$. concave lens provided the image is larger than object.$(d)$. concave lens provided the image is of the same size.
If the image formed by a convex lens is of the same size as that of the object, what is the position of the image with respect to the lens?
An object placed 4 cm in front of a converging lens produces a real image 12 cm from the lens.(a) What is the magnification of the image?(b) What is the focal length of the lens?(c) Draw a ray diagram to show the formation of image. Mark clearly F and 2F in the diagram.
Describe with the help of a ray diagram the nature, size and position of the image formed when an object is placed in front of a convex lens between focus and optical centre. State three characteristics of the image formed.
When an object is placed 10 cm in front of lens A, the image is real, inverted, magnified and formed at a great distance. When the same object is placed 10 cm in front of lens B, the image formed is real, inverted and same size as the object.(a) What is the focal length of lens A?(b) What is the focal length of lens B?(c) What is the nature of lens A?(d) What is the nature of lens B?
When an object is placed at a distance of 36 cm from a convex lens, an image of the same size as the object is formed. What will be the nature of image formed when the object is placed at a distance of:(a) 10 cm from the lens? (b) 20 cm from the lens?
(a) A 5 cm tall object is placed perpendicular to the principal axis of a convex lens of focal length 20 cm. The distance of the object from the lens is 30 cm. Find the position, nature and size of the image formed.(b) Draw a labelled ray diagram showing object distance, image distance and focal length in the above case.
A concave lens of focal length 15 cm forms an image 10 cm from the lens. How far is the object placed from the lens? Draw the ray-diagram.
(a) A small object is placed 150 mm away from a perging lens of focal length 100 mm.(i) Copy the figure below and draw rays to show how an image is formed by the lens.(ii) Calculate the distance of the image from the lens by using the lens formula.(b) The perging lens in part (a) is replaced by a converging lens also of focal length 100 mm. The object remains in the same position and an image is formed by the converging lens. Compare two properties of this image with those of the image formed by the perging lens in part (a)."
(a) Draw a ray diagram to show the formation of image of an object placed between infinity and the optical centre of a concave lens.(b) A concave lens of focal length 15 cm forms an image 10 cm from the lens. Calculatei. The distance of the object from the lens.ii. The magnification for the image formediii. The nature of the image formed.
A 10 cm tall object is placed perpendicular to the principal axis of a convex lens of focal length 12 cm. The distance of the object from the lens is 18 cm. Find the nature, position and size of the image formed.
Kickstart Your Career
Get certified by completing the course
Get Started