Một tia laser được phát ra từ nguyên tử nitơ có bước sóng 337 nm và có tổng năng lượng là 3,87 mJ. A) Tia laser trên thuộc vùng quang phổ nào của dãy quang phổ điện từ?

B)Tia laser đó chứa bao nhiêu photon?

Biết: vận tốc ánh sáng C = 3,0.108 (ms-1); hằng số Planck h = 6,626.10-34 (Js).

Agroup of students is studying convection currents. they fill two identical balloons with the same amount of helium. one balloon is placed in a freezer and the other in an area with warm air. after 10 minutes, the balloons are released from a height of 1 meter. which of the following do the students most likely observe? a. the balloons both rise. the cold balloon is larger than the warm balloon. b. the balloons rise at the same rate. both balloons are the same size. c. the warm balloon expands and rises. the cold balloon shrinks and sinks. d. the cold balloon expands and rises. the warm balloon shrinks and sinks.

What is the number of atoms in 3.54 mol s

Which statement is usually true about the relationship between activation energy and reaction rates? low activation energy barriers result in low rates. high activation energy barriers result in low rates. low activation energy barriers result in no reaction. high activation energy barriers result in no reaction.