InterviewSolution
Saved Bookmarks
| 1. |
An iron rod and another of brass, both at `27^@C` differ in length by `10^-3`m. The coefficient of linear expansion for iron is `1.1xx10^(-5)//^(@)C` and for brass is `1.9xx10^(-5)//^(@)C`. The temperature at which both these rods will have the same length isA. `0^@C`B. `152^@C`C. `175^@C`D. Data is insufficient |
|
Answer» Correct Answer - A The given data is normally isufficient to determine the result. Either the length of one of the rods at `0^@C` must be known or one has to assume that both the rods had the same length at `0^@C` which is not possible if they have the same length again at another temperature. Suppose the two rods had the same length L at `0^@C`. Then by the given problem `L[1+1.9xx10^-5xx27]-L(1+1.1xx10^-5xx27]=10^-3` `Lxx0.8xx27xx10^-5=10^-3` or `L=(10^-3)/(0.8xx27xx10^-5)m=4.63m` Hence `0^@C` is a possible choice and the rods had equal length of `4.63m` at `0^@C`. |
|