Answer:

Explanation:
Give that,
The potential difference of the electrons, 
We need to find the wavelength of the electrons.
Using the conservation of energy,

Put all the values,

So, the wavelength of the electrons is
.
<h2>Answer with Explanation </h2>
Dalton’s theory can be classified by the following hypotheses:
1) All material was formed of particles, unbreakable and strong construction segments.
2) All particles of a given component are indistinguishable in volume and characteristics
3) Compounds are determined by a mixture of two or more distinct kinds of atoms.
4) Chemical responses appeared in the rearrangement of the reacting atoms.
This theory was to explain all matter in terms of atoms and their characteristics, the law of conservation of volume and the law of constant composition.
Answer:

Explanation:
We know that
Acceleration due to gravity g is given by the formula

G= gravitational constant
M= mass of the Earth
r= radius of the earth
Let acc. due to gravity after radius is 20% greater be g_2
then

=> g1/g2 = (r_2/r_1)^2 => g2 = 9.81/1.2^2 = 6.8125
8 ∙ 10^-4 / 2 ∙ 10^2 = (8/2) ∙ ((10^-4)*(10^-2)) = <span>4 ∙ 10^-6</span>