- Find the nature, position and magnification of the images formed by a convex lens of focal length 0.20 m if the object is placed at a distance of:
- 0.50m
- 0.25m
- 0.15m
- Which of the above cases represents the use of convex lens in a film projector, in a camera, and as a magnifying glass?
Download our app for free and get started
- f = 0.20m
- u = 0.05m
$\frac{1}{\text{v}}-\frac{1}{-0.50}=\frac{1}{0.20}$
$\frac{1}{\text{v}}=\frac{1}{0.20}-\frac{1}{0.50}$
$\text{v}=0.33\text{m}$
Image is formed 0.33m behind the lens.
$\text{m}=\frac{\text{v}}{\text{u}}=\frac{0.33}{-0.50}=-0.66$
Image is real and inverted.
- $\text{u}=-0.25\text{m}$
$\frac{1}{\text{v}}-\frac{1}{-0.25}=\frac{1}{0.20}$
$\frac{1}{\text{v}}=\frac{1}{0.20}-\frac{1}{0.25}$
$\text{v}=1\text{m}$
Image is formed 1m behind the lens.
$\text{m}=\frac{\text{v}}{\text{u}}=\frac{1}{-0.25}=-4$
Image is real and inverted.
- $\text{u}=-0.15\text{m}$
$\frac{1}{\text{v}}-\frac{1}{-0.15}=\frac{1}{0.20}$
$\frac{1}{\text{v}}=\frac{1}{0.20}-\frac{1}{0.15}$
$\text{v}=-0.60\text{m}$
Image is formula 0.60m in front of the lens.
$\text{m}=\frac{\text{v}}{\text{u}}=\frac{-0.6}{-0.15}=+4$
Image is virtual and erect.
- Film projector, Case (ii)
Magnifying glass, Case (iii)
Download our appand 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
- 1View SolutionHow will you distinguish between a plane mirror, a concave mirror and a convex mirror without touching them?
- 2View SolutionDraw 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).
- 3View SolutionList some things that convex lens and concave mirror have in common.
- 4View SolutionWhy does a driver prefer to use a convex mirror as a rear-view mirror in a vehicle?
- 5View SolutionExplain why, a real image can be projected on a screen but a virtual image cannot.
- 6View SolutionAn object is placed at a distance of 15 cm. from a convex lens of focal length 20 cm. List four characteristics (nature, position, etc.) of the image formed by the lens.
- 7View SolutionTo construct ray diagram we use two light rays which are so chosen that it is easy to know their directions after reflection from the mirror. List these two rays and state the path of these rays after reflection. Use these rays to locate the image of an object placed between centres of curvature and focus of a concave mirror.
- 8View SolutionAn object is placed at a distance of 6cm from a convex mirror of focal length 12cm. Find the position and nature of the image.
- 9View SolutionIdentify the device used as a spherical mirror or lens in following cases, when the image formed is virtual and erect in each case.Object is placed between infinity and device, image formed is diminished and between pole and focus, behind it.
- 10View SolutionDraw diagram to represent the action of a concave mirror on a beam of parallel light rays. Mark on this diagram principal axis, focus F, centre of curvature C, pole P and focal length ƒ, of the concave mirror.