Choose the answer that explains the photoelectric effect.
2 answers:
1.
Answer:
Metallic plates emit electrons only when light of a certain minimum frequency shines on them.
Explanation:
As we know by Einstein's equation of energy
here we know that
= work function of metal
KE = kinetic energy of ejected electrons
E = energy of incident light
So here electrons will eject only when light of sufficient minimum energy will incident on the metal plate.
2.
Answer:
showed that individual photons have wave characteristics
Explanation:
Taylor did experiment with the source of light with very small intensity of light and then got the result of interference of light.
So here his experiment concluded that all light will show interference only due to one photon also.
So his experiment shows that one photon will give wave characteristics
You might be interested in
#1
so mass number = 238
mass number = protons + neutrons
given that
neutrons = 146
238 = protons + 146
protons = 92
#2
so mass number = 241
mass number = protons + neutrons
given that
Protons = 94
241 = 94 + neutrons
neutrons = 147
#3
A = mass number
Protons = 90
Neutrons = 137
A = protons + Neutrons
A = 90 + 137 = 227
Answer:
E ≈ 1.70 10⁵ N/C
Explanation:
The electric field is a vector quantity, so we can calculate the field of each plate and then add them. To calculate the field of a plate let's use Gauss's law
Φ = ∫ E. dA = / ε₀
To apply this law we must create a Gaussian surface that takes advantage of the symmetry of the problem. The electric field lines on the surface are perpendicular, so the Gaussian surface that will be a cylinder with the base parallel to the plate.
On this surface the normal to the base (A) is parallel to the field lines whereby the scalar product is reduced to the ordinary product. The normal on the sides of the cylinder is perpendicular to the field, therefore, the product scale is zero.
∫I E dA = /ε₀
Let's look for the load under the cylinder, let's use the concept of load density
σ = / A
= σ A
Let's write Gauss's law for this case
E A = /ε₀
E A = σ A / ε₀
E = σ / ε₀
As the field is emitted for each side of the plate the value to only one side is
E = G / 2ε₀
This expression is the same for each plate, now let's add the electric field at the requested point
R = (0.50, 0.00, 0.00) cm
We see that this point is on the X axis, between the plates that are at the points y = -1.0 cm and y = 1.0 cm, as the plates are very large the test point is between them
The negative plate has an incoming field and the positive plate has an outgoing field, the test load is always positive. The field due to the negative plate goes to the left, the field through the positive plate goes to the left at this point whereby two are added
E = E_ + E +
E = σ1 / 2ε₀ + σ2 / 2ε₀
E = 1 / 2o (σ1 + σ2)
Let's calculate the value
E = 1/2 8.85 10⁻¹² (1.00 10⁻⁶ + 2.00 10⁻⁶)
E = 3 10⁻⁶ / 17.7 10⁻¹²
E = 1,695 10⁵ N / C
E ≈ 1.70 10⁵ N/C
Answer:
b) It is impossible to tell without knowing the masses.
Explanation:
The temperature change of a substance when it receives/gives off a certain amount of heat Q is given by
where
Q is the amount of heat
m is the mass of the substance
Cs is the specific heat capacity of the substance
In this case, we have a hot piece of aluminum in contact with a cold piece of copper: the amount of heat given off by the aluminum is equal to the amount of heat absorbed by the copper, so Q is the same for the two substances. However, we see that the temperature change of the two substances depends on two other factors: the mass, m, and the specific heat, Cs. So, since we know only the specific heat of the two substances, but not their mass, we can't tell which object will experience the greater temperature change.
Answer:
Explanation:
The center of mass of the system (two girls) is constant, as the velocity of the center of mass of the system is also constant.
<u>The initial velocity of the system is zero, since both girls are at rest.</u> So the velocity of the total system at any point should be zero as well.
This is true, because there is no friction between the girls and the ground. Otherwise, the velocity of the center of mass wouldn't be constant.