A group of students are discussing how the inside of a microwave works. They are trying to figure out why the microwave is not hot after running for several minutes Which statement best describes why the inside of a microwave stays cool after use? A. When the door is opened and the heat is turned off, the inside quickly reaches thermal equilibrium with the air. The microwaves affect water molecules to generate heat through friction, so spaces without water are unaffected. C The thermal energy emitted by the microwave is absorbed by the food through heat transfer processes. D. At the end of the "cook time," the microwave uses a reverse process to extract heat from the air.

An electromagnetic wave traveling through outer space has a frequency of 429 MHz (4.29times 10^8Hz) What is the approximate wavelength of the electromagnetic wave? 0.70 meters B. 1.29 meters C. 1.43 meters 2.28 meters

Which of the following is true for an ideal gas? Particles have volume Particles exert attractive forces Collisions are elastic Temperature has no effect on particles

What happens to the volume of a gas as the temperature increases? [1. (1 Point) It decreases It increases It becomes constant It fluctuates randomly

13. For an object moving in a circle at a constant speed the net force is 100% centripetal. But the ball is changing its speed.Thus, there will be a component of force tangent to the circle to speed it up and to slow it down. At which labeled position(s) is this tangential component of force the greatest? __ 14. At which labeled position(s) is this tangential component of force the greatest? __ Propose a reason for why this is so:

Why are electrons important? Electron degeneracy is important in the core of a low-mass star after it becomes Carbon. Electron degeneracy stops the collapse of the core of a low-mass star when the core is made of Helium. A low-mass protostar evolving toward the main sequence needs enough electron to push against the contracting envelope. The core of a low-mass star just before the start of core hydrogen burning is when electrons stop the gravitational collapse.

In 2010, scientists obtained an image of an asteroid that was dangerously close to Earth. Which technology did the scientists likely use to capture the image? GPS, because it uses satellites that provide position and velocity data radio telescope, because it captures radio waves from space MRI, because it uses magnets to produce a picture submarine communication because it uses LF radio waves

What is the ultimate fate of an open universe? Individual stars die but their gas is recycled through the interstellar medium and new stars form in a never-ending process. All matter decays to a low-density sea of photons and subatomic particles. All matter eventually ends up in massive black holes. the Big Crunch Stars will expand away from each other and galaxies effectively "evaporate:

Question: As speed increases, more steering input is needed for vehicle response. Options: True False

The heat transfer process in which heat flows directly through the material is Multiple Choice conduction. convection. radiation.

Hot Questions

Which of the following describe the expansion coefficients for a general state? $a_{n}=\langle \psi _{n}\vert \psi \rangle =\int _{-\infty }^{\infty }dx\psi _{n}^{\ast }(x)\psi (x)$ $a_{n}=(\sum _{n}\vert \psi _{n}\rangle )\vert \psi \rangle $ $a_{n}=\langle \psi _{n}\vert \psi \rangle ^{\ast }=\int _{-\infty }^{\infty }dx\psi _{n}(x)\psi ^{\ast }(x)$ $a_{n}=\langle \psi _{n}\vert \psi _{m}\rangle =\int _{-\infty }^{\infty }dx\psi _{n}^{\ast }(x)\psi _{m}(x)$

A certain wave function is given by $\psi (x)=\{ \begin{matrix} A&for-a\leqslant x\leqslant a\\ 0&otherwise\end{matrix} $ Which of the following corresponds to the Fourier transform for this wave function? A sum of spherical harmonics. A sum of sines and cosines. A sum of Hankel functions. The Dirac delta function.

8> What is the random capture theory? Which theory best explains how our solar system was created?

A wave function can be expanded in basis states as $\vert \psi \rangle =\sum _{n}a_{n}\vert \psi _{n}\rangle $ What must be true of the expansion coefficients? $\sum _{n}\vert a_{n}\vert ^{2}=1$ They must be real numbers. There is no restrictions on the coefficients. $\sum _{n}a_{n}=1$

Match each statement to the wave interaction it describes. \begin{array}{|l|l|} \hline\ reflection\ &\ Waves\ bounce\ off\ an\ object.\ \\ \hline\ absorption\ &\ Waves\ are\ taken\ in\ by\ an\ object.\ \\ \hline\ transmission\ &\ Waves\ bend\ while\ passing\ from\ one\ medium\ to\ another.\ \\ \hline\ diffraction\ &\ Waves\ scatter\ through\ an\ opening\ or\ around\ an\ object.\ \\ \hline\ retraction\ &\ Waves\ go\ through\ an\ object.\ \\ \hline \end{array}

Which of the following expressions correspond to the energy-time uncertainty principle? $\Delta E\Delta t\geqslant 2\bar {h}$ $\Delta E\Delta t\geqslant \hat {h}$ $\Delta E\Delta t\geqslant \frac {h}{2}$ $\Delta \omega \Delta t\geqslant \bar {h}$

Consider the following force: A fridge magnet is pulling on a paper clip. According to Newton's third law what other force must be happening? The paper clip is pushing on the fridge magnet. The paper clip is pulling on the fridge magnet.

Which of the following correspond to the first-order shift in energies using time-independent perturbation theory? $\vert \langle \psi _{n}^{0}\vert \delta \hat {H}\vert \psi _{n}^{0}\rangle \vert ^{2}$ $\langle \psi _{n}^{0}\vert \delta \hat {H}\vert \psi _{n}^{0}\rangle $ $\sum _{m\neq n}\frac {\langle \psi _{n}^{0}\vert \delta \hat {H}\vert \psi _{n}^{0}\rangle }{E_{m}^{0}-E_$ $\sum _{m\neq n}\frac {\vert \langle \psi _{m}^{o}\vert \delta \hat {H}\vert \psi _{n}^{o})\vert ^{2}}{E_{m}^$

Which one of the following actions will increase the current ratio, all else constant? Assume the current ratio is greater than 1.0

If a wave function is given in terms of orthonormal wave functions as $\vert \psi \rangle =\frac {1}{\sqrt {5}}\vert \psi _{1}\rangle +\sqrt {\frac {3}{5}}\vert \psi _{2}\rangle +A\vert \psi _{3}\rangle $ Then what must be true about A? $\frac {1}{\sqrt {5}}$ $\frac {1}{2}$ There is not enough information to determine A. $\frac {1}{5}$