Question

give me all formulas of light- reflection and refraction class 10

Answer 1

The formula s are below

Answer 2

Answer:

• Mirror :

1. R = radius of curvature , f = focal length. then R = 2f

2. u = object distance, v =  image distance, f = focal length

    Mirror formula: $\frac{1}{v} +\frac{1}{u} = \frac{1}{f}$

3. Magnification, m = $\frac{height of image(h')}{height of object(h)} =- \frac{v}{u}$

4. In case of reflection, angle of incidence(i) = angle of reflection(r)

• Refraction:

1. From the second law of refraction, $\frac{sin i}{sin r}$ = constant

  here i = angle of incidence and r = angle of refraction.

2. Refractive index = n

  n = $\frac{speed of light in medium 1}{speed of light in medium 2}$ = $\frac{v1}{v2}$

  If, 1st medium is air and v is speed of light in second medium then we can write, n = $\frac{c}{v}$

• Lens:

1.  u = object distance, v =  image distance, f = focal length

    Mirror formula: $\frac{1}{v} -\frac{1}{u} = \frac{1}{f}$

2. Magnification, m = $\frac{height of image(h')}{height of object(h)} = \frac{v}{u}$

3. Power of lens, P = $\frac{1}{f}$

Explanation

Unit: (i) u, v, f all are measured in 'metre(m)' unit.

        (ii) n and m has no unit.

        (iii) The unit of P is 'dioptre (D)'.

Sign: In case of mirror and lens same sign convention is used.

that is: (i) The principal axis is taken as 'x' axis and centre as origin.

           (ii) The heights above principal axis are "+ve" and the heights below principal axis are "-ve".

           (iii) The right side of the centre is "+ve" and the left side of the centre is considered as "-ve".