OCR PHYSICS B G491~ 19th May 2015 AM ~ AS Physics

Let's start the mark scheme?

Yh go on !


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Q1 Units

Coulomb - As
Conductance - AV^-1

Q2

3x10^8/1.7

Q3

3.2 or 4.8 ?

Q4

Q5

Q6

Q7

Q8

Q9

Ok for
Qu1: Power - AV
Conductance: AV-1
Charge: As

Question 2 anyone? Also D, C, B for graphs as C had largest area using 1/2b*h for tensile strength

Q1 Units

Coulomb - As
Conductance - AV^-1

Q2

3x10^8/1.7

Q3

3.2 or 4.8 ?

Q4

Q5

Q6

Q7

Q8

Q9

Q1 Units

Coulomb - As
Conductance - AV^-1

Q2

3x10^8/1.7

Q3

3.2 or 4.8 ?

Q4

Q5

Q6

Q7

Q8

Q9

Q3 is 4.8 as it was 4-(-0.8) = 4+0.8 = 4.8D

Q3 is 4.8 as it was 4-(-0.8) = 4+0.8 = 4.8D

Gerrow's Unofficial mark scheme.

Add to it yourselves - I Can't remember the paper!


Q1 Units

Power AV
Coulomb - As
Conductance - AV^-1

Q2

3x10^8/1.7

Q3

3.2 or 4.8 ?

Q4

Q5

Q6

Q7

Q8

Q9

Q4. 40/280 * 4.5V (not sure about the emf of the cell)

Q3 = 3.2 D as 4.0 D is total curvature needed to be added to the incoming wavefronts and the lens adds 3.2 D and the curvature added by the eye is 0.8 D

But since u was negative so 1/f-0.8=4 so you add 0.8 = 4.8 surely?

It probably was to be honest, hopefully i might get one method mark? I was rushing the first page because our invigilators hadn't given us formulae booklets before they started the exam so i didn't have one for the first 5 minutes which was really annoying...

Let me just say what I remember

The lens one:
i) 1/1.25 = 0.8D
ii) power = 3.2D

The bits one:
i) show that Q, 2^4 = 16
ii) 500 x 300 x 4 / 8 = 75,000
iii) 75,000 x 90 x 5 = 33,750,000

The Scanning Tunnelling Microscope one:
i) sensitivity = 580 pA nm^-1
ii) diagram; one bump then two bumps next to each other
iii) explanation: it'd scan the whole surface and produce a graph of all of it, wherever a "bump" on the graph was, an atom was

The Sounds one:
i) It's logarithmic because as you go to the right it increases with a constant factor of 10
ii) frequency of highest amplitude in orchestra = 350 Hz (I think)
iii) bandwidth = 9900 Hz

The Potential Divider one:
4.5 x 40/280 = 0.64 V

For the bandwidth it was just largest - smallest?

Okay I think I remember what most of the questions were, but not the answers... anyways this might help

PS, Some of this may be wrong I can't remember completely

SECTION A
Q1 Units (3)
Power AV
Coulomb - As
Conductance - AV^-1

Q2 Refractive Index (2)
3x10^8/1.7= 1.8x10^8

Q3 Potential Divider (2)
3.2 or 4.8 ?

Q4 Bird Chirrup
Aspects of Bird Song Wave (2)
Number of oscillations (2)

Q5 Waveforms of Sounds
Logarithmic scale? (1)
Estimate of highest music frequency (1)
Estimate of bandwidth of human speech (1)

Q6 Lenses
Reading Glasses - Near point/curvature (2)
Reading Glasses - Minimum power (3)

Q7 Current Voltage Resistance
Find average (2)
Find total charge (2)

SECTION B
Q8 Conductance and resistance
Non- ohmic conductor? (1)
I think there was a two marker here but can't remember the question (2)
Find length of wire (3)
Resistivity ratio (2)
Temperature increase effect on resistivity (3)

Q9 Materials
YM Graphs (3)
Calculation of YM (2)
Alloys and Microscopic Properties (6)

Q10 Imaging
Levels=16? (1)
Size of image (2)
Size of video (2)
Magnification (3)
Resolution (2)
Another graph (2)
Graph of AFM (2)
How image is produced (1)