How many times does REM sleep generally occur during the average sleep?

One day, after pulling down your window shade, you notice that sunlight is passing through a pinhole in the shade and making a small patch of light on the far wall. you see that the patch of light seems to be a circular diffraction pattern. it appears that the central maximum is about 1 cm across and you estimate that the distance from the window shade to the wall is about 3 m. what is (a) the average wavelength of sunlight? (b) the diameter of the pinhole?

Which of the following statements is true about women and minorities in early psychology? a. in the early 20th century, numerous graduate schools recruited women and minorities to study psychology. b. opportunities in higher education were limited for women and minorities in the early 20th century due to discrimination. c. despite some obstacles, there were numerous employment opportunities for women and minorities. d. women and minorities were often selected to do academic research in an effort to make the field more diverse.

Juan created a chart to him study for a test. which headings best complete the chart? x: transparent objects y: opaque objects x: opaque objects y: transparent objects x: high frequency waves y: low frequency waves x: low frequency waves y: high frequency waves