34. two slits of width 2μm, each in an opaque material, are separated by a center-to-center distance of 6μm. a monochromatic light of wavelength 450 nm is incident on the double-slit. one finds a combined interference and diffraction pattern on the screen. (a) how many peaks of the interference will be observed in the central maximum of the diffraction pattern? (b) how many peaks of the interference will be observed if the slit width is doubled while keeping the distance between the slits same? (c) how many peaks of interference will be observed if the slits are separated by twice the distance, that is, 12μm, while keeping the widths of the slits same? (d) what will happen in (a) if instead of 450-nm light another light of wavelength 680 nm is used? (e) what is the value of the ratio of the intensity of the central peak to the intensity of the next bright peak in (a)? (f) does this ratio depend on the wavelength of the light? (g) does this ratio depend on the width or separation of the slits?

Aforce of 34.5 newtons is applied to an object at an angle of 45 º with the horizontal. what is the force acting on the object in the horizontal direction?

Why is metal often used for cooking pan?

Part f - example: finding two forces (part i) two dimensional dynamics often involves solving for two unknown quantities in two separate equations describing the total force. the block in (figure 1) has a mass m=10kg and is being pulled by a force f on a table with coefficient of static friction îľs=0.3. four forces act on it: the applied force f (directed î¸=30â above the horizontal). the force of gravity fg=mg (directly down, where g=9.8m/s2). the normal force n (directly up). the force of static friction fs (directly left, opposing any potential motion). if we want to find the size of the force necessary to just barely overcome static friction (in which case fs=îľsn), we use the condition that the sum of the forces in both directions must be 0. using some basic trigonometry, we can write this condition out for the forces in both the horizontal and vertical directions, respectively, as: fcosî¸â’îľsn=0 fsinî¸+nâ’mg=0 in order to find the magnitude of force f, we have to solve a system of two equations with both f and the normal force n unknown. use the methods we have learned to find an expression for f in terms of m, g, î¸, and îľs (no n).