33. Geometric Optics

A small light source is casting your shadow on a large wall. Both you and the light are on a line normal to the wall. You are one-fourth of the way from the light to the wall. How wide is your shadow compared to your normal width?

When light reflects off of a smooth surface, and rays that were initially parallel remain parallel, this is called…

It is proposed to store 1.00 kW•h = 3.60 * 10^6 J of electrical energy in a uniform magnetic field with magnitude 0.600 T. (b) If instead this amount of energy is to be stored in a volume (in vacuum) equivalent to a cube 40.0 cm on a side, what magnetic field is required?

It has been proposed to use large inductors as energy storage devices. (b) If the amount of energy calculated in part (a) is stored in an inductor in which the current is 80.0 A, what is the inductance?

It has been proposed to use large inductors as energy storage devices. (a) How much electrical energy is converted to light and thermal energy by a 150-W light bulb in one day?

A common optical instrument in a laser laboratory is a beam expander. One type of beam expander is shown in FIGURE P35.28. The parallel rays of a laser beam of width w₁ enter from the left. b. What is the width w₂ of the exiting laser beam?

The resolution of a digital camera is limited by two factors: diffraction by the lens, a limit of any optical system, and the fact that the sensor is divided into discrete pixels. Consider a typical point-and-shoot camera that has a 20-mm-focal-length lens and a sensor with 2.5μm x 2.5 μm pixels. c. What is the f-number of the lens for the diameter you found in part b? Your answer is a quite realistic value of the f-number at which a camera transitions from being pixel limited to being diffraction limited. For f-numbers smaller than this (larger-diameter apertures), the resolution is limited by the pixel size and does not change as you change the aperture. For f-numbers larger than this (smaller-diameter apertures), the resolution is limited by diffraction, and it gets worse as you “stop down” to smaller apertures.

A microscope has a 160 mm tube length. What focal-length objective will give total magnification ≈ 500x when used with an eyepiece having a focal length of 5.0 cm?

A microscope with a tube length of 180 mm achieves a total magnification of 800x with a 40x objective and a 20x eyepiece. The microscope is focused for viewing with a relaxed eye. Approximately how far is the sample from the objective lens?