The intensity of a light in a surface follows the inverse square law formula which can be mathematically expressed as,
I = k/d²
where I is intensity, d is distance, and k is the proportionality constant. For us to increase the intensity, we should lower the distance from the source to the surface.
Answer:
F= σ² L² /2ε₀
F = (L² ε₀/4π) ΔV² / r⁴
Explanation:
a) For this exercise we can use Coulomb's law
F = - k Q² / r²
where the negative sign indicates that the force is attractive and the value of the charge is equal to the two plates
Capacitance is defined by
C = Q / ΔV
Q = C ΔV
also the capacitance for a parallel plate capacitor is related to its shape
C = ε₀ A / r
we substitute
Q = ε₀ A ΔV / r
we substitute in the force equation
F = k (ε₀ A ΔV / r)² / r²
k = 1 / 4πε₀
F = ε₀ /4π L² ΔV² / r⁴4
F = L² ΔV² ε₀/ (4π r⁴)
F = (L² ε₀/4π) ΔV² / r⁴
b) Another way to solve the exercise is to use the relationship between the force and the electric field
F = q E
where we can calculate the field created by a plane using Gaussian law, where we use a cylinder with a base parallel to the plate as the Gaussian surface
Ф = ∫E .dA =
/ ε₀
the plate have two side
2E A = q_{int} / ε₀
E = σ / 2ε₀
σ = q_{int} / A
substituting in force
F = q σ / 2ε₀
the charge total on the other plate is
q = σ A
q = σ L²
F= σ² L² /2ε₀
Answer:
Total number of electrons

electrons removed from each sphere

Fraction of electrons transferred is given as

Explanation:
As we know that moles is defined as



so number of atoms of Al in each sphere is given as


Now number of electrons in each atom is given as
atomic number = number of electrons in each atom = 13
total number of electrons in each sphere is


Also we know that force of attraction between them is given as



now we have




Fraction of electrons transferred is given as


Answer:
a. mass density
Explanation:
<em>Land and sea breeze that occur near the shore are due to the variation of mass density of air with change in temperature.</em>
- When the air gets heated it becomes rarer in density and thus rises up in the atmosphere and its space is occupied by a cooler and denser air that flows to the place.
<em>During the day the land is warmer than the sea so the sea breeze blows and during the night the water bodies are warmer than the land so the land breeze blows.</em>
Answer:
Work done by friction along the motion is given as

Explanation:
As per work energy theorem we can say
Work done by all forces = change in kinetic energy of the system
so here car is moving from bottom to top
so here the change in kinetic energy is total work done on the car
so here we will have


now plug in all data in it


