help

[hassam]

 

[WellWIshER]

the ans is C

 

[hassam]

bt i cannot understand why it is bubbled through ethene

 

[ahmed t]

sulphuric acid dehydrates the ethanol and NaOH is used to purify by raecting with any sulphuric acid left

 

[hassam]

ans in markscheme is A.........wanted to ask that option B is of diffraction grating????

 

[hassam]

 

[hassam]

shud it be C....?

 

[hassam]

22. A boy blows gently across the top of a piece of glass tubing the low end of which is closed by his
finger so that the tube gives its fundamental note of frequency, f. While blowing, he removes his
finger from the lower end. The note he then hears will have a frequency of approximately
A ¼ f B ½ f C 2 f D 4 f
its anser shud be B ryt,,,?.....i had no markscheme dats y asking here

 

[hassam]

 

[hassam]

must reply for this last one.......?

 

[DragonCub]

The answer is B... Guess...
L2D = 41 m calculated using Pythagorean Theory
It says maximum, so at the point it is crest + crest OR trough + trough.
Anyway, L2D length exceeds L1D by one wavelength. So wavelength = 1m
f = 330 / 1 = 330 Hz

 

[hassam]

ya this was wat i thought.......also for constructive interference to occur the two distances must be integer multiples of lambda