President Obama on Wednesday brushed aside complaints that Tehran would be given 24 days to respond to requests for access to disputed nuclear sites, and said basic high school physics shows that Tehran won't be able to get away with it.

The president stressed that international inspectors would have immediate access to all known nuclear facilities. If Iran is so determined to develop a nuclear weapon that it creates a covert site, then he said the 24 days would be sufficient given the physics of nuclear activities and the trace chemicals that would be left behind.

"This is not something that you hide in the closet or you wheel off somewhere," he said. "[I]f there is nuclear material on that site, your high school physics will remind us that that leaves a trace, so we'll know that in fact there is a violation of the agreement."

"This is the most vigorous inspections regime that has ever been negotiated," he added.

Obama has faced criticism about the Iran nuclear agreement since well before it was announced Tuesday, and critics only piled on further when the details came out. These critics have said Obama originally wanted inspections "anytime, anywhere," but the final deal would set up a process that could delay those inspections by more than three weeks.

Obama said that if Iran does try to cheat, the deal has built in a one-year breakout time, which would give the U.S. time to respond with force. The agreement, he said, also builds in "snapback sanctions" that can be imposed if a violation is found.

Critics have argued that it will be difficult to re-impose sanctions once there is relief because business deals will already be under way between many countries and Iran at that point.

Just moments before, the president also said "anyone objecting to the agreement" should first read the agreement.

Afterward, he said they should explain why "they're right and [Energy Secretary] Ernie Moniz, who has a nuclear physics degree from MIT, is wrong."