Answer:
R = ρ L / A where R is the resistance and ρ the resistivity:
R2 / R1 = (L2 / A2) / (L1 / A1) = L2 * A1 / (L1 * A2)
R2 / R1 = (2 L * A) / (L * 2 A) = 1
Their resistances should be the same.
Half-life<span> is defined as the time it takes for one-</span>half<span> of the atoms of a radioactive material to disintegrate. </span>Half-lives<span> for various </span>radioisotopes<span> can range from a few microseconds to billions of years.</span>
The Joule is the SI unit of energy.
Answer: C. They are regions in which strong magnetic fields make it difficult for fresh supplies of hot, ionized gas to reach the photosphere
Explanation:
Sunspots appear dark because they are regions in which strong magnetic fields make it difficult for fresh supplies of hot, ionized gas to reach the photosphere.
Sunspots are typically cooler than their surroundings. For example, the temperature of a large sunspot can be about 4,000 Kelvin which is lower than the temperature of the photosphere around it which is about 5,800 Kelvin.
The river that flows through Rome is the Tiber.
