May 2015- Physics Paper 1 and Paper 2

[brianb97]

I did HL in TZ1... I thought both paper 1 and paper 2 were way harder than any of the practice exams I took (May 2013/2012 in both Time Zones)! I did 6 & 9 on section B... just praying that I got something right on them... 

[Hassan76]

again to those who did thermodynamics, there was this last question saying that in adiabatic change work done was i think 210J, what was the change in internal energy.. so since that was adiabatic there was no heat exchange so the change in internal energy was -210J, did i get this one right?

 

Yep, just used the first law of thermodynamics for that one.

Q = 0, Q=dU+W, W=210, -210=U

 

Damn, I really can't read the questions carefully. I somehow skipped the adiabatic part hehe... And here I've been thinking P2 went well. 

I somehow got Q to 1300 something? Can't even remember how I got that!

You used the values for the net work done given above

[Yianni]

 

 

Anyone SL TZ1? I found paper 1 really different and a lot harder than previous exams but paper 2 was a lot easier... I chose question 4.

I was time zone 1 SL. Honestly there was a lot of guessing going on there. On paper 1 I mean come on... where were the classic is this a fundamental or derived unit questions... or scalar vs vector quantity... A lot of the questions we did were in higher too, my classmates who are all higher told me (24 hours later 13:00 GMT - just to clarify) that they too had many of our questions. 

As for Paper 2 did you do the environmental that was like an amalgamation of nuclear and wind energy? -Btw that first uncertainty question on the graph was really tough with R and finding the uncertainty of V. Data analysis was far harder this year I felt, the rest was so so. Ugh and that 4 point ice cube question so annoying...

Ikr! The paper one had some really obscure questions that I hadn't seen before... especially in fields and magnetism...

 

For paper 2 the data analysis was tough but at least it was short.... so I'm praying for the markbands   

 

Ya I did the environmental question.. it wasnt too bad so I was happy with that. What option did u choose?

 

I too did the environmental question. BTW did you find 1500 GW for your answer for power production of wind?? I am as we speak revising for my options modules because I haven't revised those yet!! We do Quantum and Astrophysics, ugh so much to do, so much little time to do it in!! For that uncertainty question in the data analysis - there has been much debate amongst my classmates. I thought that since R was the volume in the cylinder after 100s then the uncertainty of R must have included the uncertainty of s, so I just minused the uncertainty of s from R to find the uncertainty of V... what did you do. Also on the environmental option the first question did you interpret it that it required us to choose between oil or nuclear or just say why we needed a 2nd power production source?

[Hassan76]

In the data analysis question, I got my slope around 1 and the y intercept aro0und 0.97. Anyone else? Also, when you took out the x intercept by equation y=mx + c to zero, did anyone find the value of x weird? Because I got some -0.98 or something and by observing and extrapolating the graph mentally to the minus x axis, it didn't look more than a -0.10. Did anyone get L as 0.93??

 

In paper 1 (Tz2) there was a question about green light being emitted from two point sources which was just NOT resolved. So the question asked how to resolve it and there were two plausible options: use red light (higher wavelength so bigger theta) and use a circular aperture (again bigger theta since 1.22 is there instead of 1). What'd you guys write? I chose red light. 

 

Ossih, what did you write for the possible binary states? 15 or 16? 

 

I had no idea what the "s" in capacitance meant, so I had to skip that question . I mean I knew it was the Farad but I forgot the definition :/ and in all my years of Physics, I have never seen a freaking s as a fundamental unit . Randomnly ticked something and probably got it wrong. 

 

In Paper 2 (tz2), for question 6, everyone found the gravitational field strength as Del V/ Del T right? And therefore from the calculation the rocket cannot escape without further engine use. 

 

Sorry about the blast of questions in your face, I'm just too excited to know everybody's else's answers . 

Also, any other Paper 1 questions anyone found challenging? I keep forgetting :/

 

That paper 1 question was about expressing capacitance in base units, which would be: charge (C = A s) / voltage (V = J / C) => charge² (A² s²) / energy (J) => A² s² / N m => A² s² / (kg m² / s²) => A² s⁴ / kg m²

Simply, knowing that there is A^2 and kg leads to a às the correct answer without even looking to seconds

Guys what about paper 1, tz2,

[Hassan76]

Who did the question on thermodynamics where you had to calc the new temperature of the gas? Did you guys get 500K?

 

Yep, I got 500K. Silly of them to ask which process was adiabatic after that question! I mean, I think they even stated it in a later question which one was adiabatic... Thanks for that free point.

I got 5000 !

[Hassan76]

Guys concerning question 9 tz2 HL p2, did anyone know how to calculate the reading of the voltmeter, and to get the uncertainty in the momentum

[Hassan76]

Guys what about the percentage of use of renewable energy, I chose 30%

[Megamind]

 

 

In the data analysis question, I got my slope around 1 and the y intercept aro0und 0.97. Anyone else? Also, when you took out the x intercept by equation y=mx + c to zero, did anyone find the value of x weird? Because I got some -0.98 or something and by observing and extrapolating the graph mentally to the minus x axis, it didn't look more than a -0.10. Did anyone get L as 0.93??

 

In paper 1 (Tz2) there was a question about green light being emitted from two point sources which was just NOT resolved. So the question asked how to resolve it and there were two plausible options: use red light (higher wavelength so bigger theta) and use a circular aperture (again bigger theta since 1.22 is there instead of 1). What'd you guys write? I chose red light. 

 

Ossih, what did you write for the possible binary states? 15 or 16? 

 

I had no idea what the "s" in capacitance meant, so I had to skip that question . I mean I knew it was the Farad but I forgot the definition :/ and in all my years of Physics, I have never seen a freaking s as a fundamental unit . Randomnly ticked something and probably got it wrong. 

 

In Paper 2 (tz2), for question 6, everyone found the gravitational field strength as Del V/ Del T right? And therefore from the calculation the rocket cannot escape without further engine use. 

 

Sorry about the blast of questions in your face, I'm just too excited to know everybody's else's answers . 

Also, any other Paper 1 questions anyone found challenging? I keep forgetting :/

 

That paper 1 question was about expressing capacitance in base units, which would be: charge (C = A s) / voltage (V = J / C) => charge² (A² s²) / energy (J) => A² s² / N m => A² s² / (kg m² / s²) => A² s⁴ / kg m²

Simply, knowing that there is A^2 and kg leads to a às the correct answer without even looking to seconds

Guys what about paper 1, tz2,

 

 

Hassan, do you remember the answer for the last MCQ in P1? The one on quantum efficiency? You remember the option you ticked there? :/

 

Also what was your answer for the one on green light sources? 

Guys what about the percentage of use of renewable energy, I chose 30%

 

 

Me too, it was a total guess though 10 was too less and 50 too much  

[Hassan76]

Concerning the Waves' question in HL p2 Section A, how did you manage to calculate the frequency, I don't think it is v over lambda as the question was worth 3 marks

[Hassan76]

In the data analysis question, I got my slope around 1 and the y intercept aro0und 0.97. Anyone else? Also, when you took out the x intercept by equation y=mx + c to zero, did anyone find the value of x weird? Because I got some -0.98 or something and by observing and extrapolating the graph mentally to the minus x axis, it didn't look more than a -0.10. Did anyone get L as 0.93??

 

In paper 1 (Tz2) there was a question about green light being emitted from two point sources which was just NOT resolved. So the question asked how to resolve it and there were two plausible options: use red light (higher wavelength so bigger theta) and use a circular aperture (again bigger theta since 1.22 is there instead of 1). What'd you guys write? I chose red light. 

 

Ossih, what did you write for the possible binary states? 15 or 16? 

 

I had no idea what the "s" in capacitance meant, so I had to skip that question . I mean I knew it was the Farad but I forgot the definition :/ and in all my years of Physics, I have never seen a freaking s as a fundamental unit . Randomnly ticked something and probably got it wrong. 

 

In Paper 2 (tz2), for question 6, everyone found the gravitational field strength as Del V/ Del T right? And therefore from the calculation the rocket cannot escape without further engine use. 

 

Sorry about the blast of questions in your face, I'm just too excited to know everybody's else's answers . 

Also, any other Paper 1 questions anyone found challenging? I keep forgetting :/

 

That paper 1 question was about expressing capacitance in base units, which would be: charge (C = A s) / voltage (V = J / C) => charge² (A² s²) / energy (J) => A² s² / N m => A² s² / (kg m² / s²) => A² s⁴ / kg m²

Simply, knowing that there is A^2 and kg leads to a às the correct answer without even looking to seconds

Guys what about paper 1, tz2,

 

Hassan, do you remember the answer for the last MCQ in P1? The one on quantum efficiency? You remember the option you ticked there? :/

 

Also what was your answer for the one on green light sources? 

Guys what about the percentage of use of renewable energy, I chose 30%

 

 

Me too, it was a total guess though 10 was too less and 50 too much

A and I'm sure of it, the strange letter is the ratio of photo electrons to photons emitted, so multiplying it by number of photons gives the number of electrons, e is the charge, and over capacitance to give the p d

In 2006 it was 18% as in Oxford study guide, 2nd page

[Hassan76]

In the data analysis question, I got my slope around 1 and the y intercept aro0und 0.97. Anyone else? Also, when you took out the x intercept by equation y=mx + c to zero, did anyone find the value of x weird? Because I got some -0.98 or something and by observing and extrapolating the graph mentally to the minus x axis, it didn't look more than a -0.10. Did anyone get L as 0.93??

 

In paper 1 (Tz2) there was a question about green light being emitted from two point sources which was just NOT resolved. So the question asked how to resolve it and there were two plausible options: use red light (higher wavelength so bigger theta) and use a circular aperture (again bigger theta since 1.22 is there instead of 1). What'd you guys write? I chose red light. 

 

Ossih, what did you write for the possible binary states? 15 or 16? 

 

I had no idea what the "s" in capacitance meant, so I had to skip that question . I mean I knew it was the Farad but I forgot the definition :/ and in all my years of Physics, I have never seen a freaking s as a fundamental unit . Randomnly ticked something and probably got it wrong. 

 

In Paper 2 (tz2), for question 6, everyone found the gravitational field strength as Del V/ Del T right? And therefore from the calculation the rocket cannot escape without further engine use. 

 

Sorry about the blast of questions in your face, I'm just too excited to know everybody's else's answers . 

Also, any other Paper 1 questions anyone found challenging? I keep forgetting :/

 

That paper 1 question was about expressing capacitance in base units, which would be: charge (C = A s) / voltage (V = J / C) => charge² (A² s²) / energy (J) => A² s² / N m => A² s² / (kg m² / s²) => A² s⁴ / kg m²

Simply, knowing that there is A^2 and kg leads to a às the correct answer without even looking to seconds

Guys what about paper 1, tz2,

 

Hassan, do you remember the answer for the last MCQ in P1? The one on quantum efficiency? You remember the option you ticked there? :/

 

Also what was your answer for the one on green light sources? 

Guys what about the percentage of use of renewable energy, I chose 30%

 

 

Me too, it was a total guess though 10 was too less and 50 too much

A and I'm sure of it, the strange letter is the ratio of photo electrons to photons emitted, so multiplying it by number of photons gives the number of electrons, e is the charge, and over capacitance to give the p dIn 2006 it was 18% as in Oxford study guide, 2nd page

For green light it is violet since it has a higher frequency so it will lead to a smaller wavelength and therefore a smaller angle that need to be resolved, this question is not unfamiliar, but the question about the bits is in the Oxford guide and I didn't know I chose 8 but it is 16

[Hassan76]

For the data analysis I didn't think that the 2 marks required a strong derivation, simply said it was the average and since it is sum of two roots not under the roots, I didn't use Pythagoras

For the gradient I got 1.11111, 0.92 for y intercept, -0.84 for x intercept, and to get L used the equation that was required to be derived as it looks like y=mx+c

[Hassan76]

Guys really our paper 2 tz2 was very easy comparing to past papers, this is not good, the boundaries will be very high, unfortunately, I wish that paper 3 outweighs it

[Megamind]

The derivation was tricky but simple once you got the principle underlying. The pendulum completes a half oscillation with its full length L therefore 

T = 0.5*2pi*Sq.root (l/g) = (pi/Sq.root g) * Sq. root of L . 

 

The pendulum completes another half oscillation with length X, therefore

T = 0.5*2pi*Sq.root (x/g) = (pi/Sq.root g) * Sq. root of X . 

 

 Therefore total time period = T = sum of both = (pi/Sq.root g) * (Sq. root X + Sq. root L) 

 

(Since the pendulum completes a quarter swing in full length L, then a quarter in the same direction with length X, then comes back a quarter period with swing X and then completes the last quarter of the period in full length L) 

Edited May 9, 2015 by Megamind

[Hassan76]

I did TZ2 HL and yeah Paper 1 was pretty interesting, you really had to think about the questions. Paper 2 I chose questions 7 and 9. The questions this year required a lot of thinking and paper 2 was more of explanations than calculations this year I feel.

How did you calculate the reading on the voltmeter in question 9? And the frequency in q 4 section A

[Hassan76]

The derivation was tricky but simple once you got the principle underlying. The pendulum completes a half oscillation with its full length L therefore 

T = 2pi*Sq.root (l/g) = (2pi/Sq.root g) * Sq. root of L . 

 

The pendulum completes another half oscillation with length X, therefore

T = 2pi*Sq.root (x/g) = (2pi/Sq.root g) * Sq. root of X . 

 

 Therefore total time period = T = sum of both = (2pi/Sq.root g) * (Sq. root X + Sq. root L) 

 

(Since the pendulum completes a quarter swing in full length L, then a quarter in the same direction with length X, then comes back a quarter period with swing X and then completes the last quarter of the period in full length L)

But it was pi not 2 pi

[Megamind]

Frequency in Q4 is supposed to be calculated by using the path difference for constructive interference, I think, i.e. even multiples of half wavelengths, given the wavelength and probably dividing it by the speed to get the frequency values. 

 

But I couldn't figure it out and didn't have time so I simply just did v/lambda which is wrong 

[Hassan76]

Frequency in Q4 is supposed to be calculated by using the path difference for constructive interference, I think, i.e. even multiples of half wavelengths, given the wavelength and probably dividing it by the speed to get the frequency values. 

 

But I couldn't figure it out and didn't have time so I simply just did v/lambda which is wrong

Frequency in Q4 is supposed to be calculated by using the path difference for constructive interference, I think, i.e. even multiples of half wavelengths, given the wavelength and probably dividing it by the speed to get the frequency values. 

 

But I couldn't figure it out and didn't have time so I simply just did v/lambda which is wrong

We didn't have information about whether it is the first ,ms econo, third .... Minimum to know n, also, these equations are in the options and in the core for the new syllabus 2016/

[Hassan76]

In the question asking for mass of the body in q7, I divided by the frequency rather than multiply by it, I knew the formula well, but forgot that this was the frequency not the period, and I forgot to say that from the graph both have the same period so same angular velocity/ frequency / omega

[IBdonesoon]

 

 

 

Anyone SL TZ1? I found paper 1 really different and a lot harder than previous exams but paper 2 was a lot easier... I chose question 4.

I was time zone 1 SL. Honestly there was a lot of guessing going on there. On paper 1 I mean come on... where were the classic is this a fundamental or derived unit questions... or scalar vs vector quantity... A lot of the questions we did were in higher too, my classmates who are all higher told me (24 hours later 13:00 GMT - just to clarify) that they too had many of our questions. 

As for Paper 2 did you do the environmental that was like an amalgamation of nuclear and wind energy? -Btw that first uncertainty question on the graph was really tough with R and finding the uncertainty of V. Data analysis was far harder this year I felt, the rest was so so. Ugh and that 4 point ice cube question so annoying...

Ikr! The paper one had some really obscure questions that I hadn't seen before... especially in fields and magnetism...

 

For paper 2 the data analysis was tough but at least it was short.... so I'm praying for the markbands   

 

Ya I did the environmental question.. it wasnt too bad so I was happy with that. What option did u choose?

 

I too did the environmental question. BTW did you find 1500 GW for your answer for power production of wind?? I am as we speak revising for my options modules because I haven't revised those yet!! We do Quantum and Astrophysics, ugh so much to do, so much little time to do it in!! For that uncertainty question in the data analysis - there has been much debate amongst my classmates. I thought that since R was the volume in the cylinder after 100s then the uncertainty of R must have included the uncertainty of s, so I just minused the uncertainty of s from R to find the uncertainty of V... what did you do. Also on the environmental option the first question did you interpret it that it required us to choose between oil or nuclear or just say why we needed a 2nd power production source?

 

Ya... For the first question I interpreted that it meant what conditions the island needed to have to be able to harness those energy forms... like it had to have enough sunlight to heat the air to produce wind currents and it had to have accessible ports to allow the imports of nuclear and fossil fuels.. all of my classmates however, put different things... I think the question itself was very weirdly worded and up to interpretation. For the wind energy one I also got 1500 GW, but it asked for the energy produced per year, so I multiplied it by the number of seconds in a year. For the first question I never thought about it like that. I interpreted it as if the uncertainty was not included, so I said that the percent uncertainty was 6%, but now that I think of it, you're probably right. For the paper 1, do you remember the question with the particle that has a mass and a charge? What fields affect it? I knew that the electric and gravitational fields play a role, but does the magnetic field have any force on the particle?