Question

Water is heated in an open pan where the air pressure is ${10}^{+5}$ Pa. The water remains a liquid, which expands by a small amount as it is heated. Determine the ratio of the heat absorbed by the water to the work done by water ($\gamma$ for water=${10}^{-3}/C,S=1cal/g{m}^{o}C$)

• A. $4.2\times {10}^3$
• B. $4.2\times {10}^5$
• C. $4.2\times {10}^2$
• D. $4.2\times {10}^4$

Answer 1

The correct option is A $4.2\times {10}^3$

Look, at your units. When something is 10−310−3 out, it's defiantly worth checking your units. If you are working in SI units the density of water is 103[kgm−3]103[kgm−3] not 1[kgm−3]1[kgm−3]. Imagine 1 metre cubed of water. It's very heavy.