 INPhO is conducted on the last Sunday of January (or on the first Sunday of February), every year, by the Homi Bhabha Centre for Science Education.School students (usually of standards 11 and 12 albeit special cases prevail) first need to qualify the National Standard Examination in Physics (NSEP) held on the last (or second last) Sunday of November of the preceding year.Among over 40,000 students appearing for the examination at almost 1400 centres across India, around 300 to 400 students are selected for INPhO based on their scores and also based on regional quotas for the states from which they appear.