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Physics: Post your doubts here!
- Thread starter XPFMember
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m a grl....
i think u have done the last part correct, but i think the second part is wrong. it shud b as i have done it... cox in 2nd part, gradient is increasing while in last part it is constant so it will b a straight line
XPFMember
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Waalaikumassalam wr wb!
Well I don't know if you know how to calculate the errors in the readings...if you want me to tell that too then do let me know
Anyway once you have the errors, this is what you have to do
Let's take for example 24 was your reading and the error is 2 , i.e. 24 +/- 2
So mark one point for the max possible value 24 + 2 = 26
And similarly for the minimum value 24 - 2 = 22
Join these two points
These two points will be one above the 24 you marked and one below it
If you still have any confusions then do let me know, I'll try to help you out inshaAllah
Waalaikumassalam wr wb!
Well I don't know if you know how to calculate the errors in the readings...if you want me to tell that too then do let me know
Anyway once you have the errors, this is what you have to do
Let's take for example 24 was your reading and the error is 2 , i.e. 24 +/- 2
So mark one point for the max possible value 24 + 2 = 26
And similarly for the minimum value 24 - 2 = 22
Join these two points
These two points will be one above the 24 you marked and one below it
If you still have any confusions then do let me know, I'll try to help you out inshaAllah
Yes i know how to calculate the errors.
So u mark these points on a graph..
The 2 points will align on the same axis then.. for every value we'll draw a straight line, and then we draw a line through all of the values to find the gradient???
I'm sorry, we didn't start with paper 5 yet, so i don't have notes for it.
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In a piezo-electric transducer such as quartz two opposite sides of the crystals are coated with thin layers of silver to act as electrical contacts.
when the crystal is unstressed, the centres of charge of positive and negative ions in any one unit coincide.
the opposite sides of crystal act as electrodes.
P.D applied across the crystal causes the crystal to change shape. (centres of +ve and -ve charges no longer coincident as charges separate)
An alternating voltage applied across the the electrodes causes the crystal to vibrate with a frequency equal to that of the applied voltage.
If the frequency of the applied voltage (in the ultrasound frequency) is equal to natural frequency of vibration of crystal, resonance will occur and the amplitude of vibration will be a maximum causing the crystals to oscillate giving rise to ultrasonic waves..
when the crystal is unstressed, the centres of charge of positive and negative ions in any one unit coincide.
the opposite sides of crystal act as electrodes.
P.D applied across the crystal causes the crystal to change shape. (centres of +ve and -ve charges no longer coincident as charges separate)
An alternating voltage applied across the the electrodes causes the crystal to vibrate with a frequency equal to that of the applied voltage.
If the frequency of the applied voltage (in the ultrasound frequency) is equal to natural frequency of vibration of crystal, resonance will occur and the amplitude of vibration will be a maximum causing the crystals to oscillate giving rise to ultrasonic waves..
part a or b?
p.d divides in series, not in parallel. each branch will hav p.d of 2V. the first branch has resistors in 1:1 ratio so p.d will be equally divided. each resistor of 5 ohms will hav p.d of 1V. so v1 is 1V.
in the second branch, the resistors are in the ratio 2:3. the p.d in the 3 ohms resistor will be 3/5 * 2 = 1.2V
so v2 = 1.2V
v1-v2 = 1 - 1.2
= -0.2 V
m getting 236 days. but marking scheme main 230 days hai
the activity A0 is stated with 2% error. we hav to get the time for 10% ka error. means original se 8% error. if original is A0, then after 8% error, it will be 0.92A0. we will consider the expression: A = A0* e^(-lambda*time)
lambda will be 0.693/half life
lambda = 0.693/(5.27*365*24*3600)
A = 0.92 A0
so the equation will be:
0.92A0 = A0 * e^(-lambda*time)
A0 will be cancelled
0.92 = e^ (-lambda*time)
ln (0.92) = -lambda*time
lambda will be 0.693/half life
lambda = 0.693/(5.27*365*24*3600)
A = 0.92 A0
so the equation will be:
0.92A0 = A0 * e^(-lambda*time)
A0 will be cancelled
0.92 = e^ (-lambda*time)
ln (0.92) = -lambda*time
Man u r a genius,thnx for replying so soon.However is there any other way for doing this question?
im really sorry. i dun know any other way
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Guys can you help me with Q5 c i in june 2004 paper 4? the ratio is coming as half with me not 2 , any ideas why is it 2?
power dissipation by direct current will be (Irms^2)*R where Irms will be Io
power dissipation by sinusoidal current will be (Irms^2)*R where Irms will be Io/(square root of 2)
[(Io^2) * R] / {[(Io/sqr root of 2)^2]*R}
Io^2*R will be cancelled
inverse of (2) will be left
inverse of 2 will be 2
ratio = 2