Table of Contents

- 1 What is sign convention of lens?
- 2 What is new Cartesian sign convention?
- 3 What is the sign of V in concave lens?
- 4 What is U and V in lens?
- 5 What is the sign of U V and F for a convex lens according to Cartesian sign convention?
- 6 Is V positive for convex lens?
- 7 Is V positive in convex mirror?
- 8 In which lens magnification is negative?
- 9 When does a converging lens form an inverted image?
- 10 Why does a meniscus lens have zero optical power?

## What is sign convention of lens?

Sign convention is a set of rules to set signs for image distance, object distance, focal length, etc for mathematical analysis of image formation. According to it: Object is always placed to the left of lens. All distances are measured from the optical centre of the mirror.

## What is new Cartesian sign convention?

Cartesian Sign Convention: In the case of spherical mirror all signs are taken from Pole of the spherical mirror, which is often called origin or origin point. This sign convention is known as New Cartesian Sign Convention. This means sign is always taken as – (negative) in front of a spherical mirror.

**What is the sign convention for convex lens?**

The sign convention of convex len is positive. In case refraction through a lens if, we take the left-hand side to be positive and right-hand side to be negative, then focal length of the second surface of the lens that is is used to determine sign.

### What is the sign of V in concave lens?

And for image distance, V in lens it is taken as positive in Convex lens since image is formed on +X side. It is taken as negative in Concave lens since image is formed in -X side of the Cartesian. In Concave mirror V is taken as positive and negative for convex mirror.

### What is U and V in lens?

where u is the distance of the object from the lens; v is the distance of the image from the lens and f is the focal length, i.e., the distance of the focus from the lens. · F. • u.

**Is V positive for concave lens?**

‘v’ is always positive for convex mirror & concave lens. Distances measured from the optic center to the right of the lens are considered +ve and t from optic center to the left are -ve.

## What is the sign of U V and F for a convex lens according to Cartesian sign convention?

See according to the New Cartesian Sign convention U i.e., the object distance is always in the left hand side of the lens or mirror i.e., to -X side. That is why U is always taken as negative. For focal length, f in lens is always taken as negative for concave and positive for convex.

## Is V positive for convex lens?

‘v’ is always positive for convex mirror & concave lens. Distances measured from the optic center to the right of the lens are considered +ve and t from optic center to the left are -ve. if you draw a line from the optic center and move towards right i.e., along the +ve x-axis then the sign is +ve.

**Is V positive or negative for convex lens?**

### Is V positive in convex mirror?

v,m,h’= positive in case of virtual image and negative in case of real image.

### In which lens magnification is negative?

Magnification is negative in a concave mirror. The magnification of a concave mirror is given by the ratio of the height of the image to the height of the object. Hence, if the image is inverted and real the magnification will be negative.

**How does a positive lens focus a converging lens?**

As mentioned above, a positive or converging lens in air focuses a collimated beam travelling along the lens axis to a spot (known as the focal point) at a distance f from the lens. Conversely, a point source of light placed at the focal point is converted into a collimated beam by the lens.

## When does a converging lens form an inverted image?

(a) When a converging lens is held farther away from the face than the lens’s focal length, an inverted image is formed. This is a case 1 image. Note that the image is in focus but the face is not, because the image is much closer to the camera taking this photograph than the face.

## Why does a meniscus lens have zero optical power?

To obtain exactly zero optical power, a meniscus lens must have slightly unequal curvatures to account for the effect of the lens’ thickness. The position of the focus of a spherical lens depends on the radii of curvature of the two facets.

**Which is the equation for the power of a lens?**

In equation form, this is P = 1 f P = 1 f , where f is the focal length of the lens, which must be given in meters (and not cm or mm). The power of a lens P has the unit diopters (D), provided that the focal length is given in meters. That is, 1D= 1 m, or 1m−1 1 D = 1 m, or 1 m − 1.