The sample size of undergraduate thesis questionnaire survey is about 300 to 500. If the study of individual differences is generally rigorous, the sample size is about 100, and if you want to be lazy, 50 or 60 copies are fine. The research topic has a large audience. If it is aimed at the public, it is recommended that the sample size be large.
The sample size needs to be determined according to the specific research topic, which has a wide audience.