Answer:
electrons exist in specified energy levels
Explanation:
In its gold-foil scattering with alpha particles, Rutherford proved that the plum-pudding model of the atom theorised by Thomson was wrong.
From his experiment, Rutherford inferred that the atom actually consists of a very small nucleus, where all the positive charge is concentrated, and the rest of the atom is basically empty, with the electrons (negatively charged) orbiting around the nucleus at very large distance.
However, Rutherford did not specify anything about the orbits of the electrons. Later, Bohr predicted that the electrons actually orbit the nucleus in specific orbits, each orbit corresponding to a specific energy level. Bohr's model found confirmation in the observation of the emission spectrum lines: when an electron in one of the higher energy level jumps down into an orbit with lower energy, the atom emits a photon which has an energy exactly equal to the difference in energy between the two orbits (and this energy of the photon corresponds to a precise wavelength).
Answer:
the Hudson Bay was covered with alpine glaciers
Explanation:
During the last glacial period, large portions of North America were covered with ice. The majority of the ice was from the ice sheets that were covering Canada and the northern part of the United States, and the alpine glaciers on the mountain ranges. Hudson Bay was all frozen at this point of time. It was not covered with alpine glaciers though, instead it was covered with the ice of the extended ice sheets, with the ice cover reaching up to 2 km in thickness.
Answer:
mass of block=2.7 gm
Explanation:
concept: Density=mass/volume
given:ρ=2700 kg/m^3 and v=250 cm^3 (in cm^3 not in m^3)
=> v= convert cm^3 to m^3
there fore= 1 cm^3=1 cm*1 cm*1 cm
i.e 1 cm^3=1/100*1/00*1/100 m^3 => 1 cm^3=1/1000000 m^3
ρ=m/v
=>mass=ρ*volume
=>mass=2700*1/10^-6
=>mass=2.7*10^-3 kg =>2.7 gm
The formula for kinetic energy is equal to 1/2mv^2, where "m" is the mass of the object (in kilograms) and "v" is equal to the velocity of the object (in meters per second). To calculate the speed, simply plug in the values and solve.
KE = 0.5mv^2
304 J = 0.5(0.3 kg)v^2 -mass converted from grams to kilograms
v = 45.02 m/s
The baseball is travelling about 45.02 meters per second.
Hope this helps!
