# What is the lens formula?

Let’s see how to use lens formula (1/v-1/u= 1/f) to locate images without having to draw ray diagrams.

## WHAT IS lens formula and magnification?

The magnification of a lens is defined as the ratio of the height of an image to the height of an object. It is also given in terms of image distance and object distance. It is equal to the ratio of image distance to that of object distance. m = h ′ h = v u. Where m= magnification.

## What is mirror formula and lens formula?

A lens is usually curved from either one or both surfaces. Mirror formula is 1/f = 1/v + 1/u. Lena formula is 1/f = 1/v – 1/u.

## WHAT IS lens formula used for?

Lens formula is a well-designed formula that is applicable for concave as well as convex lenses. The lens formula is used to find image distance, type of image formed, and the focal length (f).

## What is convex lens formula?

According to the Convex Lens equation, 1/f = 1/v + 1/u. It relates the Focal Length of a Lens with the distance of an object placed in front of it and the image formed of that object. In other words, it can be considered as an extended object AB which is placed in front of a Convex Lens.

## What is V and U in lens formula?

v = Distance of the image from the lens. u = Distance of the object from the lens. f = Focal length of the lens.

## What is magnification formula?

Magnification (m) = h / h’ Here, h is the height of the object and h’ is the height of the object. Besides, it can also be related to the object distance and image distance. So, it can be written as: m = -v / u.

## How do I calculate magnification?

1. Measure the scale bar image (beside drawing) in mm.
2. Convert to µm (multiply by 1000).
3. Magnification = scale bar image divided by actual scale bar length (written on the scale bar).

## What is power of a lens?

The power of a lens is defined as the reciprocal of its focal length. It is represented by the letter P. The power P of a lens of focal length f (in m) is given by. P=1f. The SI unit of power of a lens is ‘dioptre’.

## What is mirror formula in physics?

A mirror formula can be defined as the formula which gives the relationship between the distance of object ‘u’, the distance of image ‘v’, and the focal length of the mirror ‘f’. The mirror formula is applicable for both, plane mirrors and spherical mirrors (convex and concave mirrors).

## How is the lens formula derived?

The focal length, image distance, and object distance are all connected in the lens formula for concave and convex lenses. The formula 1/f = 1/v + 1/u can be used to establish this link. The focal length of the lens is f, and the distance of the generated image from the lens’ optical centre is v in this equation.

## WHY IS lens and mirror formula different?

The only difference between these two formulas is one having addition of mirror distance and object distance and another having subtraction of mirror distance and object distance.

## Who discovered lens formula?

Figure 78: A thin lens. is the refractive index of the lens. The above formula is usually called the lens-maker’s formula, and was discovered by Descartes. Note that the lens-maker’s formula is only valid for a thin lens whose thickness is small compared to its focal length.

## What is the SI unit of power of lens?

Power of a lens is equal to reciprocal of the focal length of the lens.SI unit of power is dioptre (D).

## What is the formula of concave?

Concave lens diverges a beam of light into a smaller, upright and virtual image. Concave lenses have thick edges and thin centre. Uses of concave lenses are treatment of myopia or short sightedness. Concave Lens Formula is: 1f=1v+1u 1 f = 1 v + 1 u .

## What is focal length formula in lens?

The focal length is half the radius of curvature and is as f=R2 f = R 2 , where f is the focal length, and R is the radius of curvature.

## What is focal length of convex lens?

Focal length of a convex lens is denoted by f which is the difference between optical centre of the lens and the principal Focus. The image would be real, inverted and smaller in size if it is formed at the focus of the lens. The refracted Ray converges on the other side of the convex lens.

## What is U and V in focal length?

U and V represent object and image distances from focus respectively.

## What is V in focal length?

v is the Image distance. f is the Focal Length given by. f = R 2. R is the radius of curvature of the spherical mirror.

## What is U in convex lens?

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.

## What are the 4 types of magnification?

There are four ways of creating magnification:  Increase the size of the object  Decrease the viewing distance Transverse magnification Telescopic magnification.

## What is magnifying power of a lens?

Magnifying power of a lens is the ratio of distance of image from the lens to the distance of object from the lens. Negative sign is used to show that the image is real. Magnifying power is given as. m=−vu. , where m=3 and u=20cm.

## Is convex lens V negative?

(c) Image distances (v) for a convex mirror is always positive because the image is always formed behind the mirror.

## What is the total magnification at 4x 10x and 40x?

Grades 1-8 typically will buy a monocular compound microscope with 3 objective lenses: 4x, 10x, 40x for maximum total magnification of 400x.