OCR PHYSICS B G494~ 11th June 2015 AM ~ A2 Physics

I said that another cable could be attached at the bottom to it swinging. What did everyone put for it being unpractical to damp the lift?

For the number of collisions per second question, did you have to estimate a value for the collision time to work out the force per particle?

Can anyone remember the value they got for epsilon and the two capcitance questions? Epsilon was a tiny number, 10^-20 I think, while the first capacitance value was something like 10-2 Farads and the second was like 20 to 40 microfarads?

I wrote adding a damper would require a huge mass that would make the building too top-heavy.

Got like 3.96x10^-20 for epsilon. Anyone else get 0.94uA for current leakage?

Did anyone else do the actuvation energy one. Was tricky. Required natural logs and complex rearring. Think i got something like 3.96x10^-20J

How did you work out current leakage? I rearranged C=Q/V to get inital current and final current, then divide change in current over time (60 seconds). I think it came out in the order of 10^-5 Farads and thus 10^1 microfarads.

How did you work out current leakage? I rearranged C=Q/V to get inital current and final current, then divide change in current over time (60 seconds). I think it came out in the order of 10^-5 Farads and thus 10^1 microfarads.

Got like 3.96x10^-20 for epsilon. Anyone else get 0.94uA for current leakage?

I got that! Joke that it was a 2 marker - I saw an almost identical question in a past paper that was a 4 marker!

How did you work out current leakage? I rearranged C=Q/V to get inital current and final current, then divide change in current over time (60 seconds). I think it came out in the order of 10^-5 Farads and thus 10^1 microfarads.

Badsically the same way. Did V/t to get volts per second then used Q=CV to get charge per second which is current was like 9.4x10^-7A of 0.94uA

what the actual **** was that section B, I got all the higher mark questions fine, but ironically left like four 2 markers.

What was that work out the mass of the Earth from R and density question all about?

Thoughts on A* boundary? I'd estimate about 47-49. Depends how many finished the paper as I found it very time consuming, many people in my school missed the entire last question due to running out of time.