Answer:
A. K = 0.546 eV
B. cooper and iron will not emit electrons
Explanation:
A. This is a problem about photoelectric effect. Then you have the following equation:
(1)
K: kinetic energy of the ejected electron
Ф: Work function of the metal = 2.48eV
h: Planck constant = 4.136*10^{-15} eV.s
λ: wavelength of light = 410nm - 750nm
c: speed of light = 3*10^8 m/s
As you can see in the equation (1), higher the wavelength, lower the kinetic energy. Then, the maximum kinetic energy is obtained with the lower wavelength (410nm). Thus, you replace the values of all variables :
B. First you calculate the energy of the photon with wavelengths of 410nm and 750nm
You compare the energies E1 and E2 with the work functions of the metals and you can conclude:
sodium = 2.3eV < E1
cesium = 2.1 eV < E1
cooper = 4.7eV > E1 (this metal will not emit electrons)
iron = 4.5eV > E1 (this metal will not emit electrons)
As this mechanical energy is associated with height, it would be "Potential Energy" in particular.
U = mgh
U = F.h
U = 1.5 * 4
U = 6 Joules
So, 6 J of energy is lost before it hits the ground.
Hope this helps!
The answer is B) A honeybee does a dance to tell the other bees where to find flowers.
Honeybees do not dance, first of all.
Second, that is not an adaptation. That is more like a message. An adaptation is changing to the environment to survive. This is not changing to the environment. They are just signaling the other bees.
A, C, and D are all adaptations. They change so that they can survive. They do a different method than usual.
~Deceptiøn
Answer:
Explanation:
Acceleration is the change in velocity over time.
The object accelerates <em>from</em> 45 meters per second <em>to </em>10 meters per second in 5 seconds. Therefore,
Substitute the values into the formula.
Solve the numerator.
Divide.
The acceleration of the object is -7 meters per square second. The acceleration is negative because the object's velocity decreases and the object slows down.
When a circuit is complete, or closed, electrons can flow from one end of a battery all the way around, through the wires, to the other end of the battery. Along its way, it will carry electrons to electrical objects that are connected to it – like the light bulb – and make them work!
