Doubts in modern physics photoelectric :mad: effect

In summary, the conversation is discussing questions related to the photoelectric effect and the properties of hydrogen atoms. The first question is asking about the number of atoms that produce three specific energy photons, while the second question is about the change in orbital moment of a hydrogen atom after absorbing energy. The third question involves the transmission of x-rays through a thin aluminum foil and the effect of increasing the heating current. The fourth question is about the relation between frequency and intensity of light and its impact on saturation current and maximum kinetic energy. The final question asks about the graph representing the relation between photo current and distance in the photoelectric effect.
  • #1
aytida88
1
0
i know theses qns may look lame but my answers are not matching with the book .pls help as i have a MAJOR EXAM coming up tomorrow:eek:

1.three photons are coming out from an excited ample of hydrogen atoms with energies of 12.1 10.2 and 1.9 eV respectively then which of the following is true?these photons must come from
1.1 atom
2.2 atoms
3.3 atoms
4.2 or 3 atoms

whats the logic here?:yuck:

2.A hydrogen atom in ground state absorbs 10.2 eV of energy.the orbital moment of it's electron will increase by...
1.05x10^-34
2.11x10^-34
3.16x10^-34
4.22x10^-34


3.x ray from a coolidge tube is incident is incident on a aluminium foil(very thin).the intensity of the x ray transmitted is found to be I0
the heating current is increased as ro increase the temperature of the filament.the intensity of x ray transmitted will be
1.zero
2.<I0
3.>I0
4.=I0

4.:yuck: :cry: :MOST IMP DBT
The frequency and intensity of light source are doubled then which of the following statement(s) is/are true...
1.saturation current remains unchaged
2.maximum kinetic energy is doubledd
answer is a is true b is false
5.this one is also urgent
a point source causes photoelectric effect from a small metal plate .which of the following graphs best represents the relation between the photo current and distance...
the graph given is a rectangular hyperbola in the first quadrant...
how??
 
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  • #2
You can start by giving use your answers and working. And by the way, question one is a completely legitimate question, think about how many electrons each hydrogen atom has and what are the energy states of a hydrogen atom.

-Hoot:smile:
 
  • #3



Dear student,

I understand your concerns and frustration with the modern physics photoelectric effect. It is a complex and challenging topic, and it is normal to have doubts and questions about it. However, I want to assure you that with practice and a good understanding of the fundamental principles, you will be able to master this topic.

1. The answer to this question is 3 atoms. This is because each photon carries a specific energy, and the total energy of the three photons (12.1 + 10.2 + 1.9 eV) can only come from three separate hydrogen atoms. The logic here is that energy is conserved, and it cannot be created or destroyed.

2. The correct answer is 2.11x10^-34. This is because when an electron absorbs energy, it moves to a higher energy level, and its orbital moment increases accordingly. The amount of increase in orbital moment can be calculated using the formula h/(2π), where h is Planck's constant. In this case, the energy absorbed is 10.2 eV, so the increase in orbital moment would be (10.2 eV)(1.6x10^-19 J/eV)/(6.63x10^-34 J s)/(2π) = 2.11x10^-34.

3. The correct answer is 3. >I0. This is because increasing the heating current will increase the temperature of the filament, which in turn will increase the intensity of the x-rays emitted. This will result in a higher intensity of transmitted x-rays as well.

4. The correct answer is a is true, b is false. This is because the saturation current is dependent on the intensity of the light source, not its frequency. So doubling the frequency of the light will not change the saturation current. However, the maximum kinetic energy of the emitted electrons is directly proportional to the frequency of the light, so doubling the frequency will double the maximum kinetic energy.

5. The graph given is a rectangular hyperbola because the photo current is directly proportional to the intensity of the light source. As the distance increases, the intensity decreases, and hence the photo current decreases. This relationship can be represented by a rectangular hyperbola.

I hope this helps you in your exam tomorrow. Remember to stay calm and think logically, and I am sure you will do well. Good luck!
 

1. What is the photoelectric effect?

The photoelectric effect is a phenomenon in which electrons are emitted from a material when it is exposed to electromagnetic radiation, such as light.

2. What is the significance of the photoelectric effect in modern physics?

The photoelectric effect was one of the key experiments that led to the development of quantum mechanics, which is the foundation of modern physics. It also provided evidence for the particle-like nature of light.

3. How does the photoelectric effect support the wave-particle duality of light?

The photoelectric effect demonstrates that light can behave as both a wave and a particle. The emission of electrons from a material is a particle-like behavior, while the interference patterns observed in the experiment indicate a wave-like nature.

4. What is the threshold frequency in the photoelectric effect?

The threshold frequency is the minimum frequency of light required to cause the emission of electrons from a material in the photoelectric effect. It is different for every material and is determined by the binding energy of the electrons in the material.

5. What is the work function in the photoelectric effect?

The work function is the minimum amount of energy required to remove an electron from a material. It is equivalent to the threshold frequency multiplied by Planck's constant. The work function is a property of the material and can vary depending on its composition.

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