Please help me with physics hw i dont understand

Question

1) which of the following gives good evidence for the particle nature of EM radiation?

A) photoelectric effect

B) electron probability regions

C) interference patterns

D) diffraction

2) which of the following gives good evidence for the wave nature of EM radiation

A) interference patterns

B) the photoelectric effect

C) existence of photons

D) matter waves

3) when studying the photoelectric effect, which parameters did scientists think were relevant for electrons to be released or not in both the wave and particle models

A) intensity only for both models

B) frequency only for both models

C) frequency and intensity for the wave model; frequency only for the particle model

D) frequency and intensity for the particle model; frequency only for the wave model

4) an image represents the gaps between allowed energy levels for electrons. Which model best describes this phenomenon

A) the particle model because electrons are particles

B) the particle model because the arrows represent discrete particle-like jumps

C) the wave model because the arrows show that the energy transfer is continuous

D) the wave model because electrons orbit the atoms nucleus in a continuous way

5) considering that an up quark has a charge of +2/3 and a down quark has a charge of -1/3, which of the following represents the correct quark combination for a proton

A) 2 up, 1 down

B) 0 up, 3 down

C) 2 down, 1 up

D) 3 down, 3 up

6) if an atom gives off electromagnetic radiation with a frequency of 2.0 × 10^(15)s^(-1), what is the radiations energy

A) 3.0 × 10^48 J

B) 1.3 × 10^-18 J

C) 9.9 × 10^-41 J

D) 3.3 × 10^-49 J

7) a nuclide of phosphorus 30/15 P decays into a nuclide of silicon 30/14 Si. In order to satisfy charge conservation and lepton number conservation the other products must be

A) and electron and a neutrino

B) and electron and an antinuetrino

C) a positron and an antineutrino

D) a positron and a neutrino

8) nuclide X has a higher rate of decay than nuclide Y. Based on this information, which of the following statements must be true

A) the daughter nuclides of X are more abundant than those of Y

B) nuclide Y has a larger half-life than nuclide X

C) Nuclide X is less abundant than nuclide Y

D) nuclide Y has a shorter half-life than nuclide X

Answer 1

Answers:

1 A

2 A

3 A

4 B

5 A

6 B

7 D

8 D

Answer 2

1)

A) Photoelectric effect is evidence of particle nature of EM radiation.

B) Electron probability region is a model, and as such cannot serve as evidence.

C) Interference patterns are evidence of wave nature of EM radiation.

D) Diffraction is evidence of wave nature of EM radiation.

2)

A) Interference patterns are evidence of wave nature of EM radiation.

B) Photoelectric effect is evidence of particle nature of EM radiation.

C) Existence of photons is a model, and as such cannot serve as evidence.

D) Matter waves are a model, and as such cannot serve as evidence.

3)

I do not quite understand the question because it uses the past tense and I do not know

to what period it refers.

Before Einstein's 1905 paper, light was assumed to be wave, and therefore its energy was

entirely determined by its intensity.

That was not supported by observation, in which frequency determined whether electrons

would be released.

The 1905 paper presented the particle model of light, where the energy releasing an electron

is determined by frequency, not intensity.

Intensity merely determines the number of electrons released.

4)

The gaps between energy levels are explained by the wave model, where an electron is

a standing wave, and only discrete wavelengths are possible.

Options A) and B), referring to the particle model, are not the right answer.

C) Is not right because energy transfer is not continuous, it happens in discrete jumps.

D) is the only remaining option, but I do not understand the relevance of continuous orbiting.

5)

Just add up the charges for each option and see which gives you the charge of a proton,

namely +1.

Option D) does give you the charge of +1, but proton has only 3 quarks.

6)

Use the formula E = hf to calculate the energy E.

7)

The original nuclide has charge of +15, while the resulting nuclide has change of only +14.

The missing change must fly away in the form of a positron, which has a charge of +1.

The positron has lepton number -1; therefore something with lepton number of +1

must also fly away -- a neutrino.

8)

Rate of decay is inversely proportional to half-life;

so that gives us the relationship between half-lives.

But it does not give give us information about abundance, because that depends on

abundance of the nuclides before the experiment.