Answer:

Explanation:
<u>Given:</u>
- Diameter of the plates of the capacitor, D = 21 cm = 0.21 m.
- Distance of separation between the plates, d = 1.0 cm = 0.01 m.
- Minimum value of electric field that produces spark,

When the dimensions of the plate of the capacitor is comparatively much larger than the distance of separation between the plates, then, according to the Gauss' law of electrostatics, the value of the electric field strength in the region between the plates of the capacitor is given by

where,
= surface charge density of the plate of the capacitor =
.
= magnitude of the charge on each of the plate.
= surface area of each of the plate =
= electrical permittivity of free space, having value = 
For the minimum value of electric field that produces spark,

It is the maximum value of the magnitude of charge which can be added up to each of the plates of the capacitor.
Answer:
force becomes one - ninth
Explanation:
According to Coulomb's law in electrostatics, two charges can exert a force of attraction or repulsion on each other which is directly proportional to the product of two charges and inversely proportional to the square of distance between them.
Here both the charges remains same but the distance is variable.
So, we can say that
.... (1)
Where d be the distance between the tow charges
As the distance between two charges increases by factor of three, let the new force be F'.
.... (2)
Divide equation (2) by equation (1), we get


Thus, the force becomes one - ninth times the initial force.
Yes, in general, metalloids are slightly reactive.
Answer:
241.7 s
Explanation:
We are given that
Charge of particle=
Kinetic energy of particle=
Initial time=
Final potential difference=
We have to find the time t after that the particle is released and traveled through a potential difference 0.351 V.
We know that

Using the formula


Initial voltage=

Using the formula





Hence, after 241.7 s the particle is released has it traveled through a potential difference of 0.351 V.
Answer:
2.295 eV
Explanation:
maximum wavelength, λ = 542 nm = 542 x 10^-9 m
The work function of the metal is defined as the minimum amount of energy falling on the metal so that the photo electrons just ejects the surface of metal.

where, h is the Plank's constant and c be the speed of light
h = 6.634 x 10^-34 Js
c = 3 x 10^8 m/s


Wo = 2.295 eV
Thus, the work function of this metal is 2.295 eV.