University Physics III: Waves, Optics & Modern

Use this for “A 0.65 m guitar string under 72 N tension has 0.4 g of mass per meter. Find its fundamental and the wavelength of its third harmonic.”

Use this for “A loudspeaker sends out 2.5 W of sound evenly in all directions. What are the intensity and the sound level 15 m away?”

Use this for “Red light of 650 nm passes a slit 0.05 mm wide onto a wall 2.5 m away. How wide is the central bright band?”

Use this for “A grating has 300 lines per mm. At what angle is the second-order line of 656 nm light, and how many orders can be seen?”

Use this for “A soap film (n = 1.33) is 250 nm thick. Which visible wavelength does it reflect most strongly?”

Use this for “A ship moving at 0.7c fires a probe forward at 0.5c relative to the ship. How fast does the probe move as seen from the planet?”

Use this for “A proton (rest energy 938.3 MeV) moves at 0.8c. Find its total energy, its kinetic energy and its momentum in MeV/c.”

Use this for “A rocket passes Earth at 0.8c. An event happens 1,200 m away along its path, 2,000 m of ct after they meet. Where and when is it in the rocket’s frame?”

Use this for “Ultraviolet light of 200 nm falls on a copper plate whose work function is 4.7 eV. What stopping potential halts the fastest electrons, and what is copper’s threshold wavelength?”

Use this for “Electrons in a microscope are accelerated from rest through 2500 V. What is their de Broglie wavelength?”

Use this for “An electron in a hydrogen atom falls from n = 4 to n = 1. Find the energy of each level, the photon’s wavelength and the series it belongs to.”

Use this for “An electron is confined to a region 0.1 nm wide. What is the least uncertainty in its momentum and in its speed?”

Use this for “A sample holds 4 × 10¹² nuclei of phosphorus-32, whose half-life is 14.3 days. How many are left after 30 days, and what is the activity then?”

Use this for “Radium-226 (226.025410 u) gives off an alpha particle (4.002603 u) and becomes radon-222 (222.017578 u). How much energy does each decay release?”

Use this for “A glass lens (n = 1.5) has radii +20 cm and −20 cm. Find f.”

Use this for “An object is 20 cm before a 10 cm lens; a 20 cm lens stands 50 cm behind it. Where is the final image and how big?”

Use this for “Estimate the Kα X-ray energy and wavelength of copper (Z = 29).”

Use this for “For l = 3, find |L|, the allowed Lz, and the angle between L and the z-axis when m = 2.”

Use this for “A copper wire of 1 mm² carries 1 A. Find the electrons’ drift speed.”

Use this for “Silicon has a band gap of 1.12 eV. What is the longest wavelength it absorbs?”

Use this for “The pion has a rest energy of 139.6 MeV. Estimate the range of the force it carries.”

Use this for “The cosmic microwave background is 2.725 K today. How hot was it at z = 1,100, and where does today’s spectrum peak?”