Answer:
1853–1924: Passenger railways and expansion
The 14-carriage train was hauled by three steam locomotives: the Sahib, Sindh, and Sultan. ... The first passenger train in eastern India ran from Howrah (near Calcutta) to Hoogly, a distance of 24 miles (39 km), on 15 August 1854.
<span>Unpredictable floods, small & defenseless region, and limited natural resources.</span>
Answer:
The man
Explanation:
because of the medical field
Answer: When asteroids enter the atmosphere of Earth or any other planet, they are called meteorites. Typically, asteroids are too small to form a circular shape, unlike dwarf planets or comets.
Explanation:
Why are meteoroids not considered dwarf planets?
<em>Key difference: A dwarf planet is “a celestial body in direct orbit of the Sun that is massive enough for its shape to be controlled by gravitation, but that unlike a planet has not cleared its orbital region of other objects.” An asteroid, on the other hand, is a large chunk of rock that orbits around the sun.</em>
Answer:
B and C
Explanation:
B. In a given rock sample, the amount of Silicon-32 isotopes gets divided in half about every 170yrs.
This is the concept of half-life. Half life is the time take for half of a radioactive isotope to disintegrate. The shorter the half life the faster the isotope disintegrates.
From the question, we were told that it would take 170yrs for half of the isotope of Silicon to disintegrate to Phosphorus. This is the half life.
C. The half life can be used to determine the amount of Si-32 that has decayed from the time closure temperature was reached.
The closure temperature is very important in radioactivity. It is the temperature at which a system has cooled and there is no resulting disintegration of parent and daughter isotopes.
From first order kinetics, we know that the rate at which radioactive elements decay at any time is directly proportional to the number of radioactive atoms present. A knowledge of the half life helps to figure out the number of atoms that has decayed in time.
