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Questions in physics

[Free] Which best explains what happens when an electron moves from an excited state to the ground state? A. The electron absorbs energy as it moves to a lower energy level. B. The electron absorbs energy as it moves to a higher energy level. C. The electron releases energy as it moves to a higher energy level. D. The electron releases energy as it moves to a lower energy level.

[Free] Particle A has very little mass in comparison to Particle B. Both particles are in the same atom. Which is the best conclusion about Particles A and B? A. They have the same charge. B. They are located in the nucleus together. C. Particle A has a positive charge, and Particle B is neutral. D. Particle A orbits the nucleus, and Particle B is located in the nucleus.

[Free] Light of wavelength [tex]$5 \times 10^{-7} m$[/tex] falls on a sensitive metal plate with photoelectric work function 1.90 eV. Find the kinetic energy of the photoelectrons emitted and the stopping potential. (given [tex]$h =6.62 \times 10^{-34} Js$[/tex])

[Free] Taden has found a table of the atmospheric layers of the Sun. However, he can't make out the names of the layers in the chart. [tex] \begin{tabular}{|l|l|l|l|} \hline & \multicolumn{1}{|c|}{ A } & \multicolumn{1}{c|}{ B } & \multicolumn{1}{c|}{ C } \\ \hline Position & Lowest & Middle & Outermost \\ \hline Thickness & 100 km & 2000 km & Millions of kilometers \\ \hline Temperature & 5,500 & 6,000 to 20,000 & $2,000,000$ \\ \hline \end{tabular} [/tex] What are the names of the Sun's layers described in columns A, B, and C? A. Corona; B: Photosphere; C: Chromosphere B. Core; B: Chromosphere; C: Photosphere C. Chromosphere; B: Corona; C: Core D. Photosphere; B: Chromosphere; C: Corona

[Free] Charges of +5 C and -9 C are at a distance of 1 m from each other. Which diagram represents the force between the two charges?

[Free] An observer wants to determine a moving object's momentum. The observer measures the object's mass. Which other variable must the observer determine? A. force B. acceleration C. position D. velocity

[Free] What effect does a convex lens have on distant objects? A. It makes them appear larger and clearer B. It blocks light from passing C. It spreads light rays from the object D. It makes them appear smaller

[Free] An astronaut is on a space walk floating in space. She tosses a wrench to a second astronaut in front of her. What happens to the first astronaut? A. The astronaut drifts forward at an increasing speed. B. The astronaut remains in her current position. C. The astronaut drifts forward toward the wrench. D. The astronaut drifts backward away from the wrench.

[Free] What effect does a convex lens have on distant objects? a. It makes them appear larger and clearer b. It blocks light from passing c. It spreads light rays from the object d. It makes them appear smaller

[Free] Select the correct answer. Kepler's third law, [tex]P^2=k A^3$[/tex], shows the relationship between a planet's orbital period [tex]$(P)$[/tex] and the length of its semi-major axis [tex]$(A)$[/tex]. Which statement is true about Kepler's law? A. The orbital period is measured in units of time, and the semi-major axis is measured in units of mass. B. The value k is constant for each of the eight planets in our solar system. C. For a body orbiting the Sun, increasing the orbital period increases the length of the semi-major axis. D. To calculate the value of k for a planet in our solar system, find [tex]A^3+P^2$[/tex] for the planet.