Questions

Passivity of iron is due to formation of an extremely thin and impervious film of ferrosoferric oxide Fe3O4on the surface of iron. Chromic acid, being a powerful oxidising agent (like nitric acid ) renders iron passive. 

Volatile memory is computer memory that requires power to maintain the stored information. It is a temporary memeory which cannot contain information permanently.

Example :: RAM or Random Access Memory

The ozone layer is a region of Earth's Stratosphere that absorbs most of the Sun's ultraviolet (UV) radiation. It contains high concentrations of ozone (O3) in relation to other parts of the atmosphere, although still small in relation to other gases in the stratosphere.

The Atmosphere is divided into 4 layers according to major changes in temperature. They are :

1. Troposphere,

2. Stratosphere,

3. Mesosphere  and

4. Thermosphere.

The farther away from earth, the thinner the atmosphere gets.

India has acquired the top position among 30 developing countries on ease of doing business at the 2017 A.T. Kearney Global Retail Development Index (GRDI). The 2017 GRDI titled “The Age of Focus” ranked China at second place, followed by Malaysia, Turkey, United Arab Emirates (UAE) and Vietnam. The 16th edition of GRDI ranked top 30 developing countries for retail investment worldwide and analyzed 25 macroeconomic and retail-specific variables to help retailers devise successful global strategies to identify emerging market investment opportunities.

Answer D is correct because a sunk cost is a project expense that will eventualy need to be paid. Answer A is incorrect because a fixed cost remains constant, regardless of any change in a company's activity. Answer B is incorrect because direct cost can be directly linked to producing specific goods or services. Answer C is incorrect because a variable cost changes in proportion to a change in the company's activity or business.

It will stop at a height where the weight of the balloon with contents is equal to the weight of air displaced by it, i.e , when the upthrust is equal to the downthrust. The question of bursting will depend on how much difference of pressure inside and outside , the material of the balloon can withstand. It is assumed the balloon is filled with a lighter than air gas like hydrogen or helium.