Question

class 10th science chapter - Light all formulas

Answer 1

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

2. lens formula:
$\frac{1}{f} = \frac{1}{v} - \frac{1}{u}$

3. magnification in mirror:
$m = \frac{h2}{h} = - \frac{v}{u}$

4. magnification in lens:
$m = \frac{h2}{h} = \frac{v}{u}$

5. power of lens:
$p = \frac{1}{f}$

6. refractive index:
$n21 = \frac{v1}{v2} \\ and \\ \: n12 = \frac{v2}{v1}$

7. absolute refractive index:
$nm = \frac{c}{v}$

8. Snell's law:
$\frac{ \sin(i) }{ \sin(r) } = k$

where f = focal length, v = image distance, u = object distance, h = object height, h2 = image height, m = magnification, p = power, v1 = speed of light in medium 1 and v2 = that in medium 2, c = speed of light in air/vacuum, k = constant.