Thomson's results from experiments with cathode ray tubes produced a big change in scientific thought about atoms because <u>his results gave the first evidence that atoms were made of smaller particles.</u>
Particularly, he proved the existence of negatively charged sub-atomic particles that are called as electrons which together with a positively charged nucleus form an atomic unit.
Thomson's plum pudding model of the atom had negatively-charged electrons embedded within a positively-charged "soup." Thomson also made the following conclusions from his experiment:
- The cathode ray is composed of negatively-charged particles.
- The particles must be as part of an atom because the mass of each particle is only ~ 1/2000
compared to one hydrogen atom mass.
- Within the atoms of all elements, these subatomic particles are found.
Initially it was controversial, but later Thomson's discoveries were gradually accepted by scientists. After then, his cathode ray particles were given a name called as electrons.
As we know that block of steel is continue to be in moving state
so here the friction must be kinetic friction between two surface
so we know that formula of kinetic friction must be
now we have
now from the above equation we have
So here we need atleast 14.25 N force to continue sliding the box now as per given options all forces which are less than 14.25 N is not correct
Hence correct answer must be 18.0 N
<u>D) 18.0 N</u>
We can base this on the equation of thermal expansion.
ΔL = L₀αΔT
where
ΔL is the expansion of length upon heating
L₀ is the initial length
α is the coefficient of linear expansion
ΔT is the temperature difference
So, if α for Aluminum is greater than α for Copper, then after heating, aluminum would be longer than copper.
D is the amount of space object takes up
