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Questions in physics

📝 Answered - Large nuclei like uranium are radioactive because A. they are too large for the strong force to counteract electrostatic repulsion. B. none of the above C. they have too much mass. D. they can hold extra particles, such as beta rays. E. there are too many protons.

📝 Answered - The table below shows the approximate distances of two stars from Earth. | Name of star | Approximate distance from Earth (in light years) | | :------------- | :--------------------------------------------- | | Sirius | 8.6 | | Epsilon Eridani | 10.5 | A scientist uses a space telescope to photograph the two stars. Which of these is a correct conclusion about the photographs of the two stars as taken by the scientist? A. It takes more than 10 years to photograph Sirius. B. It takes more than 10 years to photograph Epsilon Eridani. C. The photographs show a more recent picture of Sirius than Epsilon Eridani. D. The photographs show a more recent picture of Epsilon Eridani than Sirius.

📝 Answered - Fill in the missing information in the table: | Decay Type | Mass of particle | Charge of particle | Symbol | | :---------------- | :--------------- | :----------------- | :-------------- | | Alpha | [?] | +2 | ${ }_2^4 He$ | | Beta | 0 | | | | | 0 | | ${ }_0^0 \gamma$ | | Positron Emission | | +1 | |

📝 Answered - The intensity, or loudness, of a sound can be measured in decibels $(d B)$, according to the equation $/(d B)=10 olog \left[\frac{1}{l_0}\right]$, where $I$ is the intensity of a given sound and $I_0$ is the threshold of hearing intensity. What is the intensity, in decibels, $[I(d B)]$, when $I=10^8\left(I_0\right)$ ?

📝 Answered - An electric device delivers a current of [tex]$15.0 A$[/tex] for 30 seconds. How many electrons flow through it?

📝 Answered - Which describes the relationship between the frequency, wavelength, and speed of a wave as the wave travels through different media? A. As speed changes, wavelength changes and frequency remains constant. B. As speed changes, frequency changes and wavelength remains constant. C. As speed changes, wavelength and frequency change. D. As speed changes, wavelength and frequency remain constant.

📝 Answered - Which explains the information needed to calculate speed and velocity? A. Both require the total distance, but velocity also requires time and displacement. B. Both require time, but velocity requires displacement and speed requires distance. C. Speed requires displacement, while velocity requires distance. D. Speed does not require time, while velocity does require time.

📝 Answered - Experiment with the interactive tool and determine which of the following trends are true or not: As temperature goes up... * the peak wavelength goes up. * stars get bluer and the peak wavelength drops. * stars get redder. * the total power output goes up. True or False

📝 Answered - An electric device delivers a current of [tex]$15.0 A$[/tex] for 30 seconds. How many electrons flow through it?

📝 Answered - A boat initially at rest accelerates uniformly to $29.4 m / s$ over 7.60 s. What is the acceleration of the boat? $a=[?] m / s^2$