Atoms of the same element will always have the same number of Question Blank but will have different numbers of Question Blank if their mass numbers are different.

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?

Can anybody me with this? ? (picture included.)

How would a small bar magnet be oriented when placed at position x?