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
Answer:
a) 29.4 J
b) - 29.4 J
Explanation:
Given:
Mass of the book, m = 2 kg
Height above the floor, h = 1.5 m
Now,
the work done by the person will be = Force applied on the book × displacement of the book
thus,
Work done by the person = mg × h
where, g is the acceleration due to gravity
thus, on substituting the values, we get
Work done by the person = 2 × 9.8 × 1.5 = 29.4 J
now,
for the force applied by the gravitational pull (downwards) the displacement is in opposite direction (upwards) to the force of the gravity.
Thus,
work done by the gravity will be negative
therefore, the work done by the gravity = - mg × h
or
work done by the gravity = - 29.4 J
The answer is C. The mass of the platinum sample is greater than the mass of the lead sample. As I explained in a previous answer, if they are the same volume, but one is heavier, then it must be more dense. In this particular example, the platinum is more dense than the lead, and therefore has more mass.
As charges move in a closed loop, they gain as much energy as they lose.
<h3>What is principle of
conservation of energy?</h3>
- According to the principle of conservation of energy, in a closed or isolated system, the total energy of the system is always conserved.
- The energy gained by the particles or charges in a closed system is equal to the energy lost by the charges.
Thus, we can conclude the following based on principles of conservation of energy;
- As charges move in a closed loop, they gain as much energy as they lose.
Learn more about conservation of energy here: brainly.com/question/166559
