Physics: Post your doubts here!

[SaifAliSamoo]

https://sites.google.com/site/urbangeekclassroomsg/using-word-documents/table-of-formulae

 

[blueberryyums]

Well, past papers do help a lot. I guess just redo and DONT forget to read the book. Textbook is really helpful. Pastpapers alone do nothing.

I doubt I have enough time to redo the past years again but I am planning to go through the questions I have done, the ones I don't fully understand and get my knowledge back hopefully, early on tonight. Are you ready for the paper tomorrow?

 

[TaffsAsLevel]

Any body have all the relationships between quantities of double slits like what happens to brightness and other aspects when a quantity in the equation of double slit is increased or decreased?

 

[asd]

I doubt I have enough time to redo the past years again but I am planning to go through the questions I have done, the ones I don't fully understand and get my knowledge back hopefully, early on tonight. Are you ready for the paper tomorrow?

Yes, I guess.

 

[daredevil]

Its AD aunty

ms mein unhon ne BD se nikaal k usay 12 mein se minus kia hai.... *dumasses they cie people* -_-
acha one more thing about the same question ... y don't we take into acount the resistance of the wire (10 ohm) like BD mein sirf length ki ratio q letey hain?? resistance b use nahi karein gay??

 

[asd]

Any body have all the relationships between quantities of double slits like what happens to brightness and other aspects when a quantity in the equation of double slit is increased or decreased?

No quantity in the equation affects the brightness. Its the intensity that does.

 

[TaffsAsLevel]

No quantity in the equation affects the brightness. Its the intensity that does.

So basically it's just proportionality problem? and when it comes to brightness it's only amplitude and intensity?

 

[A star]

ms mein unhon ne BD se nikaal k usay 12 mein se minus kia hai.... *dumasses they cie people* -_-
acha one more thing about the same question ... y don't we take into acount the resistance of the wire (10 ohm) like BD mein sirf length ki ratio q letey hain?? resistance b use nahi karein gay??

well v is directly proportinal to R which is directly proportional to length

 

[A star]

Yes, I guess.

what happenes if we use bright light me do we have to mention k brightness waghaira does not increase or just that light will diff

 

[asd]

ms mein unhon ne BD se nikaal k usay 12 mein se minus kia hai.... *dumasses they cie people* -_-
acha one more thing about the same question ... y don't we take into acount the resistance of the wire (10 ohm) like BD mein sirf length ki ratio q letey hain?? resistance b use nahi karein gay??

We do consider the resistance. Multiply the ratio of length by the resistance. Thats what I did ig.

 

[syed1995]

syed1995 and A star
now u both better give us some answers because main ne bohaat mshkil se dhoonda hai ye question!!

Since there is same current in R and C.. We will use the formula .. P=IV .. I being constant P is directly proportional to V.

Now since the pd across C is larger than pd across R. The power will be greater at C than R.

Hope you get it.

 

[asd]

what happenes if we use bright light me do we have to mention k brightness waghaira does not increase or just that light will diff

You use a bright light (that is with higher intensity) Fringes are going to be brighter. and its always advisable to make a comment that there will be no effect on the fringe separation.

 

[syed1995]

You use a bright light (that is with higher intensity) Fringes are going to be brighter. and its always advisable to make a comment that there will be no effect on the fringe separation.

Nor will there be a difference at the brightness of the dark fringes. Only Bright fringes intensity increases.

 

[daredevil]

y

Since there is same current in R and C.. We will use the formula .. P=IV .. I being constant P is directly proportional to V.

Now since the pd across C is larger than pd across R. The power will be greater at C than R.

Hope you get it.

eah i got it

 

[asd]

Nor will there be a difference at the brightness of the dark fringes. Only Bright fringes intensity increases.

yeah exactly, how can I forget that. :|

 

[TaffsAsLevel]

What about June 2004 paper 2, question on the wave fronts on fig 6.1, how do we know where to draw the line in the figure for the destructive and constructive interference, I know its where the two diffracted waves intersect but which ones are destructive and constructive?

 

[asd]

So basically it's just proportionality problem? and when it comes to brightness it's only amplitude and intensity?

Yes. You got it right.

 

[asd]

What about June 2004 paper 2, question on the wave fronts on fig 6.1, how do we know where to draw the line in the figure for the destructive and constructive interference, I know its where the two diffracted waves intersect but which ones are destructive and constructive?

Constuctive where they intersect, and destructive just draw a line through where one of the waves' wavefronts are exactly in between the wavefronts of the other.
) . ) Like this if you get it lol

 

[TaffsAsLevel]

Nor will there be a difference at the brightness of the dark fringes. Only Bright fringes intensity increases.

Yes because anyway the amplitudes of the interfering waves are equal in magnitude but 180 degrees phase so any how they cancel each other out, and yes only bright fringes gets brighter

 

[syed1995]

Yes. You got it right.

If we increase the intensity of ones of the slits in a double slit experiment while the other remains constant.. both the dark and bright fringes will become brighter yeah?