How do I know if the image is real or virtual?

Click For Summary
SUMMARY

The discussion centers on determining whether an image produced by a lens is real or virtual, specifically using the magnification formula m = - (v/u). The user grapples with understanding the conditions under which an image is considered real or virtual, particularly in relation to the object's position relative to the focal length of a converging lens. It is established that when the object is positioned between the optical center and the focal length, the image is virtual, as exemplified by the use of a magnifying glass.

PREREQUISITES
  • Understanding of lens optics, specifically converging lenses
  • Familiarity with the magnification formula m = - (v/u)
  • Knowledge of focal length and its significance in image formation
  • Ability to interpret ray diagrams for lenses
NEXT STEPS
  • Study ray diagrams for converging lenses to visualize image formation
  • Learn about the properties of real and virtual images in optical systems
  • Explore the concept of focal length and its impact on image characteristics
  • Investigate practical applications of lenses, such as magnifying glasses and cameras
USEFUL FOR

Students of physics, particularly those studying optics, educators teaching lens behavior, and anyone interested in the practical applications of lenses in everyday devices.

izMuted
Messages
4
Reaction score
1

Homework Statement


ae476d4f6593d54e328badcc49f9ecd0.png

I know that the object distance is 15 using the equation m = - (v/u)
(+ or - depending on real / virtual) 2 = (+ or -) 30/u
u = 15

However how do I know if the image is real or virtual?

Homework Equations


m = - (v/u)

The Attempt at a Solution

 
Physics news on Phys.org
Have you tried drawing the diagram, something like this:
u14l5c1.gif


Where would the image have to be to be bigger than the object?

Which side is known as the real side, which side is known as the virtual side and why?
 
How do I draw the diagram when I don't know if the object is within / outside the focal length?
Also I used to think that because the image is bigger it must be virtual, however there are some diagrams on the internet where the image is bigger and the object is outside the focal length, like here:
u14l5da6.gif
 
"the lens is used as a magnifying glass"- usually when using a magnifying glass is the image virtual or real?
 
  • Like
Likes izMuted
As far as I know, in a converging lens, only when the object is between the optical centre and the focal length that the image is virtual (i.e. the setting used in a magnifying glass).
 
  • Like
Likes izMuted
Ah yeah the magnifying glass part makes sense - thanks for explaining
 
  • Like
Likes Sarahborg

Thread 'Magnitude of buoyant force in fluids of different densities'

The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?
View full post »

Similar threads

Mirror placed horizontally between two half convex lenses
  • · Replies 11 ·
Replies
11
Views
1K
Lens Maker's Formula - Confusion in the derivation
  • · Replies 15 ·
Replies
15
Views
2K
Are Real Images Always Inverted and Virtual Always Erect in Ray Optics?
  • · Replies 9 ·
Replies
9
Views
8K
Focal length of the eyepiece lens in a compound microscope
  • · Replies 7 ·
Replies
7
Views
2K
Analyzing this 2-lens optical system
  • · Replies 5 ·
Replies
5
Views
2K
Magnification, when is it negative?
  • · Replies 2 ·
Replies
2
Views
10K
Could the Image from the First Mirror Be Real for the Second Mirror?
  • · Replies 7 ·
Replies
7
Views
2K
Microscope Optics: questions and calculations
  • · Replies 12 ·
Replies
12
Views
2K
Is the Solution for Rotation of Spherical Mirrors Incorrect?
  • · Replies 16 ·
Replies
16
Views
2K
Understanding Focal Length: Solving for Image Position with 1/u + 1/v = 1/f
  • · Replies 10 ·
Replies
10
Views
26K