Answer: high iridium levels in a 66- million-year-old clay layer in Denmark and Italy
Explanation:
I don’t know about 3 but I know that 4 is solid, 5 is you’ll feel the vibration first, 6 is you’ll see the lightning first because the speed of light is faster than the speed of sound and 7 is sound waves need a medium to travel and light waves don’t, sound waves are longitudinal and light waves are transverse, and sound waves are mechanical waves while light waves are electromagnetic waves
A 70.-kg person exposed to ⁹⁰Sr absorbs 6.0X10⁵ β⁻ particles, each with an energy of 8.74X10⁻¹⁴ J.
<h3>What is β⁻ particles ?</h3>
A beta particle, also known as a beta ray or beta radiation (symbol ), is a highly energetic, swiftly moving electron or positron that is released during the radioactive disintegration of an atomic nucleus. Beta decay occurs in two ways: decay and + decay, which result in the production of electrons and positrons, respectively.
In air, beta particles with an energy of 0.5 MeV have a range of roughly one meter; the range is energy-dependent.
Ionizing radiation of the sort known as beta particles is regarded, for the purposes of radiation protection, as being more ionizing than gamma rays but less ionizing than alpha particles. The damage to live tissue increases as the ionizing effect increases, but so does the radiation's penetration power.
To learn more about β⁻ particles from the given link:
brainly.com/question/10111545
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Answer:
44° to 45°
Explanation:
The altitude of Polaris star when viewed from New York City is somewhat between 44° to 45°. However, Polaris is directly overhead at the North Pole (90° of latitude); in other words, the angle between Polaris and the horizon at the North Pole is 90°. This angle is called "the altitude" of Polaris.