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 $25cm$ on the tape, the real length of the given piece of wood must be:

• A. $25cm$
• B. $<25cm$
• C. $>25cm$
• D. Cannot say

Answer 1

The correct option is B $<25cm$

Since at 20 degree temperature steel tape measures correct measurement of wood
Now at 0 degree length is 25 cm therefore, when temperature is shifted the scale reading 25 cm will increase and therefore the length which is 25 cm at 0 degree will be less than 25 cm at 20 degree.
option (B)