Why are the bridge declared unsafe after long use?

Why are the bridges declared unsafe after long use ?

Assertion : The bridges declared unsafe after a long use. Reason : Elastic strength of bridges losses with time

Statement-1: The bridges are declared unsafe after a long use. Statement-2: Elastic strength of bridges losses with time.

In the following questions, a statement of assertion is followed by a statement of reason. Mark the correct choice as (a) If both assertion and reason are true and reason is the correct explanation of assertion. (b) If both assertion and reason are true but reason is not the correct explanation of assertion. (c ) If assertion is true but reason is false. (d) If assertion and reason are false. Q. Assertion: The bridges are declared unsafe after long use. Reason: Elastic strength of bridges losed with time.

Wheatstone bridge can be used

Metre bridge is used to

Why a dry cell becomes dead after a long time even if it is not used ?