Stellar evolution
We may see thousands of stars in the dark sky. Our universe consists of billions of stars. Stars may appear tiny to us but they are huge balls of gasses. Sun is a star of average size. Some stars are even a thousand times larger than the sun. The stars do not exist forever they have a certain lifetime. The life span of the sun is about 10 billion years. The star undergoes various changes during its lifetime, this process is called stellar evolution. The structure of the sun-like star is shown below.
Red Shift
It is an astronomical phenomenon. In this phenomenon, increase in wavelength with corresponding decrease in photon energy and frequency of radiation of light. It is the displacement of spectrum of any kind of astronomical object to the longer wavelengths (red) side.
Electric Potential Energy
A +3.0-nC charge Q is initially at rest a distance of 10 cm (r1) from a +5.0-nC charge q fixed at the origin. Naturally, the Coulomb force accelerates Q away from q, eventually reaching 15 cm (r2).
- What is the work done by the electric field between r1r1 and r2r2?
- How much kinetic energy does Q have at r2r2?
My question is about the image attached. The part in the equation circled in blue is positive, and the part circled in red is negative. Can you explain how that negative sign appeared?
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Solved in 2 steps with 2 images
