The so-called "velocity-time" graph is actually a "speed-time" graph. At any point
on it, the 'x'-coordinate is a time, and the 'y'-coordinate is the speed at that time.
'Velocity' is a speed AND a direction. Without a direction, you do not have a velocity,
and these graphs never show the direction of the motion. It seems to me that it would be
pretty tough to draw a graph that shows the direction of motion at every instant of time,
so my take is that you'll never see a true "velocity-time" graph.
At best, it would need a second line on it, whose 'y'-coordinate referred to a second
axis, calibrated in angle and representing the 'bearing' or 'heading' of the motion at
each instant. The graph of uniform circular motion, for example, would have a straight
horizontal line for speed, and a 'sawtooth' wave for direction.
Answer:
Democritus
Explanation:
He called these "uncuttable" pieces atomos. This is where the modern term atom comes from. Democritus first introduced the idea of the atom almost 2500 years ago.
Answer:
a) True. The number of photoelectrons is proportional to the amount (intensity) of the incident beam. From the expression above we see that threshold frequency cannot emit electrons.
b) λ = c / f
Therefore, as the wavelength increases, the frequency decreases and therefore the energy of the photoelectrons emitted,
c) threshold energy
h f =Ф
Explanation:
It's photoelectric effect was fully explained by Einstein by the expression
Knox = h f - fi
Where K is the kinetic energy of the photoelectrons, f the frequency of the incident radiation and fi the work function of the metal
a) True. The number of photoelectrons is proportional to the amount (intensity) of the incident beam. From the expression above we see that threshold frequency cannot emit electrons.
b) wavelength is related to frequency
λ = c / f
Therefore, as the wavelength increases, the frequency decreases and therefore the energy of the photoelectrons emitted, so there is a wavelength from which electrons cannot be removed from the metal.
c) As the work increases, more frequency radiation is needed to remove the electrons, because there is a threshold energy
h f =Ф
<h3>
Answer: True</h3>
For example, a very dense metal will sink to the bottom while something like wood will float on the surface. The wood is less dense compared to the water, which is why it floats. Density is the measure of how much stuff you can pack in a certain volume. The higher the density, the more stuff per volume. Think of it like packing a suitcase. If there's barely anything in there, then we can say its density is low. The more stuff crammed in the suitcase will increase the density (and therefore the weight), while keeping the volume the same.
Is there a multiple choice?
