Recent content by somecelxis

Homework Statement a patient who is undergoing cancer theraphy is given 10 mins of irradiation from a radioactive source that has half life = 2 years. If the same source is to be used for same treatment 2 years later , how long should the patient should be irradiated? the ans is 20 mins .. can...

Homework Statement the expected frequency for the age of (21-30, 31-36, more than or equal to 37) for operation is less than 5 , so combination of these numbers are required for the expected frequency to be more than or equal to 5 . my question is which numbers should i combine? would my ans...

In my book, the oxidation process is carried out using the conc h2s04 ... For alcohol.. This is the first time I saw it with conc hno3...

Homework Statement is it possible to use conc HNO3 instead of H2SO4 to allow the reaction of oxidation of cyclohexanol to haxane-1.6 dioic acid to occur? how can the reaction occur? cyclohexanol is seconary alcohol , it should be oxidised to ketone am i right? but it's oxidised to carboxylic...

i was told that [FONT=Courier New]The H on the side chain is a "Benzylic hydrogen atom" it is very reactive and even chlorine will react mostly by attacking at that position. Bromine, as shown, is much more selective. does it mean benzylic hydrogen atom more reactive than aliphatic hydrogen...

Homework Statement can someone teach me how do you convert this reactant to get the product? I consider this as free radical substituition reaction and in the presence of UV , then the H atom in the 2 CH3 will also be substituted... i want ony the H atom on the carbon bonded to C to be...

thanks all, i managed to solve the question above.

my E(X^2) = 19159... why it's wrong? then what should it be?

Homework Statement sample data as bellow: 46,48,51,50,45,53,50,48 to find the estimated varaince , the ans with 6.10 is correct... why can't i use this way? my ans for second way is 19051. which is wrong...Homework EquationsThe Attempt at a Solution Var(x) = E(x^2) -( E(x)^2) = 19159- (...

i don't know how to use LATEX. estimated mean = 70/10 = 7 estimated variance = 1/(10-1) x ( 522 - (70x70)/10 ) = 32/9 symmetrical interval = 7- 1.960 surd (4/10) , 7+ 1.960 surd (4/10)

please allow me to post the whole question here... A government wants to study X , the time taken by an employee are chosen and the information obtained is summarised as sum of X= 70 , sum of X^2 = 522 .. (i) Find unbiased estimate for mean and variance X (2) If X is distributed normally and...

( 7- 1.960 x (surd(4/10)) , 7+1.960 x (surd(4/10)) )

Homework Statement If X is distributed normally with mean = 7 and the variance of X is 4 , calculate a 95% interval for mean of X . size interval is 10 Homework Equations The Attempt at a Solution here's my working : ( 4- 1.960 x (surd(4/10)) , 4+1.960 x (surd(4/10)) ) my ans is incorrect...

as the (f1-f2) increases, Period of beat = 1/(f1-f2) decreases. i knew this ... but this only involve maths ... can you explain in a 'physics' way?

Homework Statement i read some online notes. from there , i know that if the beat frequnecy ( difference in frequncies between 2 waves ) is low , then the time taken for two waves to be in phase again is very long... which means more number of waves has to be produced for two waves to be in...