Answer:
λ = 4.1638 10⁻⁷ m
Explanation:
The photoelectric effect was explained by Einstein assuming that the radiation acts like particles and the equation that describes the process is
K = h f -Ф
where K is the kinetic energy of the emitted electrons, hf the energy of the photons according to Planck's equation and Ф the work function of the material
In this case they give us the kinetic energy of the electrons
K = 0.7 eV
The sodium work function is tabulated Ф = 2.28 eV
Let's find the frequency of the photons
f = (K + Ф) / h
Planck's constant is
h = 6.626 10⁻³⁴ J s (1 eV / 1.6 10⁻¹⁹ J) = 4.136 10⁻¹⁵ eV s
f = (0.7 + 2.28) / 4.136 10⁻¹⁵
f = 7.2050 10¹⁴ Hz
let's find the wavelength using the relationship between speed and frequency and wavelength
c = λ f
λ = c / f
λ = 3 10⁸ / 7.205 10¹⁴
λ = 4.1638 10⁻⁷ m
B. It reflects a lot of light, transmits almost no light, and absorbs some light.
Answer:
0.83 m/s
Explanation:
FIrst of all, we have to find the time of flight, i.e. the time the baseball needs to reach the ground. This can be done by using the equation for the vertical motion:
where
h is the initial height
u = 0 is the initial vertical velocity
g = 9.8 m/s^2 is the acceleration of gravity
t is the time
Substituting h = 1.8 m and solving for t,
We know that the horizontal distance travelled by the ball is
d = 0.5 m
Therefore, we can find the horizontal velocity (which is constant during the whole motion):
I got no solution! but I believe the answer is zero.
I added like terms so
X+ 2=2x+1
—————
x^2 +6 =x +6
Then
X+1=2x
————
x^2+0=x
Then
3x=-1
———
x^3
So
-3
—
-X^2 = 1
So no solution :/
But if you do the equations separate the answer is 0 because
The top equation will equal 1 and the bottom will equal zero.
Answer:
Explanation:
As we know that the refractive index of the water is
also we know that refractive index of the glass is
now we know by Snell's law
so we have
now if no light will refract into the water then in that case
now we have