Answer:
E = h f = h c / λ energy of single photon
n E = 4.00E-11 W/m^2 energy required for visibility
n h c / λ = 4.00E-11 number of photons required for visibility (per square meter)
n = 4.00E-11 * 5.00E-7 / (6.63E-34 * 3.00E8)
n = 20.0E-18 / 19.9 E-26 = 1.00E8
100 million photons would be required on 1 m^2 to create visibility
a / A = π * (3.6E-3)^2 / 1 = 4.07E-5 fraction of area available
4.07E-5 * 1.00E8 = 4.07E3 photons required
I am pretty sure that non of the listed options above is correct. Current
, resistance, potential difference and induction all don't have the dimension of an energy that d<span>ifference in electrical potential energy should have. Quite a tricky question, be careful.</span>
Answer:
891 excess electrons must be present on each sphere
Explanation:
One Charge = q1 = q
Force = F = 4.57*10^-21 N
Other charge = q2 =q
Distance = r = 20 cm = 0.2 m
permittivity of free space = eo =8.854×10−12 C^2/ (N.m^2)
Using Coulomb's law,
F=[1/4pieo]q1q2/r^2
F = [1/4pieo]q^2 / r^2
q^2 =F [4pieo]r^2
q = r*sq rt F[4pieo]
q=0.2* sq rt[ 4.57 x 10^-21]*[4*3.1416*8.854*10^-12]
q = 1.42614*10^ -16 C
number of electrons = n = q/e=1.42614*10^ -16 /1.6*10^-19
n =891
891 excess electrons must be present on each sphere
Impulse describes the change of momentum. Since we don't know the momentum of the soccer ball before the hit, this question is hard to answer. If you assume the momentum of the ball before the hit was p = 0, then the change in momentum is just Δp = Impulse = mv.
It's solubility. Solubility is a measure of the ability of a solute to dissolve in a solvent; maximum amount of solute that will dissolve in solvent at a specific temperature. Solute is substance being dissolved. Solvent is the substance that is doing the dissolving; the part of the solution that is present in the greatest quantity.
