Q1: Measuring with a 30 m chain, 0.01 m too short, introduces

ANS:C - positive cumulative error

{ POSITIVE ERROR }:: 'Measured length is "more than" the actual length.
The length of the chain is "shorter than " the standard length.
The temperature is "lower than" at which the tape was calibrated.

{NEGATIVE ERROR}:: 'Measured length is less than the actual length.
The length of the chain is greater than the standard length.

{COMPANSATIVE ERROR }:: 'Incorrect holding of the chain.
'Variation in pull. The Correct answer is a positive commutative error.

Error =measured length - true length.
When the chain is too short ML >T. L.
SO, ERROR IS POSITIVE and it is commutative because every time we are using the same chain means we are adding. If an elongated chain (suppose 2 metres too long) is kept on the ground. It will cover a distance of 32 metres but it will show you the 30-metre distance. Answer C is correct because they already declared that the tape is 30 m but the distance measured is less than the tape length by 0.01m. Hence it is positive cumulative error. If the chain is short then we will have much reading and thus measured length minus actual length will be a positive value. Answer is C, because if the length of the chain gets short then we measured less value. Because noted down more value.

So, an error will be cumulative positive in nature and correction will be negative.