A convex lens forms a real and inverted image of a needle at a distance of 50 cm from it. Where is the needle placed in front of the convex lens if the image is equal to the size of the object? Also, find the power of the lens.
Download our app for free and get startedPlay store
v = + 50 cm
Since image is real and of same size. The position of image should be double the focal length.
Hence, the object should be at 2f.
V = 2f = 50, f = 25 cm.
Power = 1/f = 100/25 = 4D
art

Download our app
and get started for free

Experience the future of education. Simply download our apps or reach out to us for more information. Let's shape the future of learning together!No signup needed.*

Similar Questions

  • 1
    Where would the image be formed by a convex mirror if the object is placed:
    1. Between infinity and pole of the mirror?
    2. At infinity?
    Draw labelled ray-diagrams to show the formation of image in both the cases.
    View Solution
  • 2
    Show the lateral displacement of the ray on the diagram.
    View Solution
  • 3
    ‘‘A concave mirror of focal length 15cm can form a magnified erect as well as inverted image of an object placed in front of it.’’ Justify this statement stating the position of the object with respect to the pole of the mirror in both cases for obtaining the images.
    View Solution
  • 4
    Does the incident and emergent ray coincide in the process of refraction through glass slab? Give reason.
    View Solution
  • 5
    Draw ray diagrams showing the image formation by a convex lens when an object is placed:
    Between optical centre and focus of the lens.
    View Solution
  • 6
    What is meant by ‘refraction of light’? Draw a labelled ray diagram to show the refraction of light.
    View Solution
  • 7
    How does the light have to enter the glass:
    1. To produce a large amount of bending?
    2. For no refraction to happen?
    View Solution
  • 8
    “A ray of light incident on a rectangular glass slab immersed in any medium emerges parallel to itself.” Draw labeled ray diagram to justify this statement.
    View Solution
  • 9
    With the help of a ray diagram, determine the position, nature and size of the image formed of an object placed at the centre of curvature of a concave mirror.
    View Solution
  • 10
    State three characteristics of the image formed by a convex mirror.
    View Solution