When moving oxidation numbers down as subscripts in an ionic bond, you do not include the charge either positive or negative.
The process of moving oxidation number down as subscript is known as exchange of valency.
The combining power is used in exchanging valency and this is oxidation number exchanged. The number corresponds to the number of electrons usually lost or gained or shared by atoms of elements during chemical combination or the number of positive or negative charges carried by ions.
The combining power is exchanged as simple whole number ratio during the formation of chemical formulae of compounds.
Military personnel also use periscopes in some gun turrets and in armoured vehicles. More complex periscopes using prisms or advanced fibre optics instead of mirrors and providing magnification operate on submarines and in various fields of science
The question doesn't describe any experiment. If the same experiment is repeated, no matter how many times, the acceleration due to gravity will remain the same as it was during the non-existent original experiment, and will have no effect on anything.
By applying formula P= pgh, where P is pressure, p is density, g is gravitational acceleration (9.8 m\s2) and h is height of water level. Putting values in the formula, you can have the correct answer.
