Question

A steel tape gives correct measurement at ${20}^{\circ }C$. A piece of wood is being measured with the steel tape at $0^{\circ }C$. The reading is $25\text{cm}$ on the tape, the real length of the given piece of wood must be

• A. $25\text{cm}$
• B. $<25\text{cm}$
• C. $>25\text{cm}$
• D. Cannot say

Answer 1

The correct option is B $<25\text{cm}$

At ${20}^{\circ }\text{C}$ temperature steel tape measures correct measurement of wood.
Now at $0^{\circ }\text{C}$ length is $25\text{cm}$.
Since temperature is decreased, length of the steel tape will decrease.
So, whatever we will measure will show more than the a actual length.
So the real length of wood must be less than $25\text{cm}$.