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A2 Physics | Post your doubts here

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(a) when it would be parallel(horizontal) the magnetic field strenght would pass through it for a longer distance (2.8cm) .when it is perpendicular magnetic field strength passes through for a very short distance which is thickness of the coil.

(b)(i) torque = force x distance
2.1 x 10^3 = F x 0.028m
F=0.075N

bii there are no field lines cutting the side BC so there wont be a force there .
 
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:ROFLMAO: like finding a needle in a haystack,
Okay will do, thanks though :)
Here it is:
From Part i) The Intensity that is reflected back from the muscle bone boundary is 0.331 i.e 0.331 x 0.389 I

The key to this part is that you have to deduce the Intersity reflection coefficient from part ii).
When the ultrasound reaches the surface of the muscle, 0.661 will be reflected and 0.389 will pass through ----> 0.331 x 0.389 x 0.389 I = 0.05 I
 
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calculate current in 6 kiloohm resistor
 

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Here it is:
From Part i) The Intensity that is reflected back from the muscle bone boundary is 0.331 i.e 0.331 x 0.389 I

The key to this part is that you have to deduce the Intersity reflection coefficient from part ii).
When the ultrasound reaches the surface of the muscle, 0.661 will be reflected and 0.389 will pass through ----> 0.331 x 0.389 x 0.389 I = 0.05 I
Jazakallah brother
 
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So basically, you just draw a graph similar to that one, but each individual peak is every 20µs and the lwhole waveform takes 200µs to complete?
exactly! the amplitude is not given so dont worry about the amplitude !
 
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thank
For Q9 b) the difference in the uncertainties is 10%-2% =8%

That's an uncertainty of 0.08. So to calculate the activity for when the source is not decaying 0.08, it would be decaying 1-0.08= 0.92.
so the activity= 0.092 decay constant=0.693/half life .. and the rest is just
A
= A0 exp(–ln2 t / T½
)
thanku angelic
 
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