A wheel and axel because the axel is a rod in the door and the knob is the wheel portion. However, these things can also be considered a lever.
It is because the weight is equal to each other and balances out. example war ships have tons of metal, but it spreads the weight on the water
The answer should be 1.6 kilometers.
The illumination of the book is found to be approximately equal to 15 lx.
Option 1.
Explanation:
Luminous flux is the measure of power of the light emitted from a source and illumination is the property of the light to illuminate a given surface when it falls on the surface. So the measure of the region the light flux illuminates the surface is termed as illumination.
As here the luminous flux is given as 1759 lm and the distance of the object which has to be illuminated is placed 3 m away from the source ,the illumination is found to be directly proportional to the luminous flux and inversely proportional to the square of the distance between them

So, the illumination of the book is found to be approximately equal to 15 lx.