Which statement about agitation time and sieve adequacy is correct?

• A. If the mass passing after one minute exceeds 0.5% the sieving is adequate
• B. If the mass passing after one minute exceeds 0.5% the sieving is not adequate
• C. If the mass passing after one minute is less than 0.5% the sieving is not adequate
• D. If the mass passing after one minute is less than 0.5% the sieving is adequate

Answer: (B)

The main idea here is that a sieve must control particle sizes consistently, and agitation time is a standard test to check the sieve’s performance. After one minute of shaking, only a very small amount of material should pass through the sieve. The limit is 0.5% of the sample mass. If more than 0.5% passes in that minute, the sieve isn’t performing adequately—this can indicate worn or damaged mesh or other screening issues that would bias the gradation results. When the passing amount is 0.5% or less, the sieve is considered acceptable, with the exact boundary often described as not exceeding 0.5%.

So, the statement that matches this idea is that more than 0.5% passing after one minute means the sieve is not adequate. The other options mix up the implication or rely on the strict “less than” wording, which can exclude the acceptable boundary case.