In a stack there are 5 books each of thickness 20mm and 5 paper sheets each of thickness 0.016 mm. What is the total thickness of the stack.

A student measures the thickness of a human hair by looking at it through a microscope of magnification 100. He makes 20 observations and finds that the average width of the hair in the field of view of the microscope is 3.5 mm. What is the estimate on the thickness of hair ?

If the thickness of 500 sheets of paper is 3.5 cm,then what would be the thickness of 275 sheets of this paper ?

A sweet seller has 420 kaju baths and 130 badam barfis. She wants to stack them in such a way that each stack has the same number and they take up the least area of the tray. What is the number that can be placed in each stack for this purpose ?

Lenses are often coated with a thin film to reduce the intesntiy of reflected light. If the index of refraction of the coating is 1.3 ,what is the smallest thickness that wilo give minimum relfaction of yello light (lambda=5,800 overset@A) ?

A double slit apparatus is immersed in a liquid of refractive index 1.33. It has slit separation of 1 mm and distance between he plane of slits and screen is 1.33 m. The slits are illuminated by a parallel beam of light whose wavelength in air is 6300 oversetcircA One of the slits of the apparatus is covered with a thin glass sheet of refractive index 1.53. Find the smallest thickness of the sheet to bring the adjacent minimum on the axis.

How many grams of silver could be plated out on a serving tray by elelctolysis of a solution containing silver in +1 oxidation state for a period of 8.0 hours at a current of 8.46 amperes? What is the area of the tray if the thickness of the silver plating is 0.0025 cm? density of silver is 10.5 g/cm^3 .