A sinusoidally oscillating current I ( t ) I(t) with an amplitude of 9.55 A 9.55 A and a frequency of 879 cycles per second 879 cycles per second is carried by a long, straight wire. A rectangular loop of copper wire with dimensions b = 72.2 cm b=72.2 cm by c = 32.5 cm c=32.5 cm is located a = 80.2 cm a=80.2 cm from the straight wire, and is coplanar with it. Calculate the average power P avg Pavg dissipated by the loop if its resistance is 64.3 Ω .

Which statement is true for light passing into a medium that is more optically dense than the first medium through which it past

The motor m applies a time-varying force of f (200 t) n, where t is in seconds. box b with mass 200 kg starts from rest, and the coefficients of kinetic and static friction are 0.2 and us 0.3 the acceleration due to gravity is g 9.8 m/s2 b 300 a) find the time ' when the box starts to move. b) calculate the speed of the crate at 3 s c) calculate the power delivered by the motor at t 3 s

Some material consisting of a collection of microscopic objects is kept at a high temperature. a photon detector capable of detecting photon energies from infrared through ultraviolet observes photons emitted with energies of 0.3 ev, 0.5 ev, 0.8 ev, 2.0ev, 2.5ev, and 2.8ev. these are the only photon energies observed. (a) draw and label a possible energy-level diagram for one of the microscopic objects, which has four bound states. on the diagram, indicate the transitions corresponding to the emitted photons. explain briefly. (b) would a spring–mass model be a good model for these microscopic objects? why or why not? (c) the material is now cooled down to a very low temperature, and the photon detector stops detecting photon emissions. next, a beam of light with a continuous range of energies from infrared through ultraviolet shines on the material, and the photon detector observes the beam of light after it passes through the material. what photon energies in this beam of light are observed to be significantly reduced in intensity (“dark absorption lines”)? explain briefly.