Lv 31,272 points

Allen

• PC to TV using HDMI cable but no sound from TV headphones?

Using HDMI cable to connect laptop to LCD tv. i get both sound and picture on the tv. I have headphones connected to the TV. They get sound when watching digital tv channels but not when watching whats coming from the pc (the speakers on the tv do get sound but this does not seem to go to the headphones connected to audio out)

• PC to TV using HDMI cable but no sound from TV headphones?

Using HDMI cable to connect laptop to LCD tv. i get both sound and picture on the tv. I have headphones connected to the TV. They get sound when watching digital tv channels but not when watching whats coming from the pc (the speakers on the tv do get sound but this does not seem to go to the headphones connected to audio out)

• In atomic spectroscopy, which of the following is NOT correct?

a. A hollow cathode lamp is the required light source for atomic emission spectroscopy.

b. Absorption by molecular species in the flame causes spectral interference.

c. Graphite Furnace AAS is a more sensitive analytical method with lower detection limits for most metals than flame AAS.

d. Pressure broadening of atomic spectral lines increases with temperature.

e. Doppler broadening of atomic spectral lines increases with temperature.

I believe the answer to this question is b, can someone confirm

Thanks

• Calculate the mass of copper sulfate (CuSO4.5H2O) required to prepare 250 mL solution of 1000 mg Cu L-1.?

How do u do this type of question. Thanks

• What is the probability that exactly 4/7 parts have greater lengths than 26cm given normal distribution,mean?

Suppose that the lengths of automotive parts on a production line can be regarded as independent observations from a normal distribution with mean 25cm and standard deviation 4cm. Seven parts are randomly selected from the line. What is the probability that exactly four of these parts have lengths greater than 26cm.

Not sure what i am doing wrong. using sd as 4/(7^.5).

Any help would be good. Some steps would be good. Thanks

• Hypothesis testing about the mean of a population. Type Two error?

Testing a hypothesis about the mean (mu) of a population.

H0: mu=35 vs H1: mu>35

There is a type two error if

a. you do not reject H0 when mu is really 40

b. rejects H0 when mu really is 40

c. you do not reject H0 when mu really is 35

d. you do not reject H0 when mu really is 30

e. you reject H0 when mu really 45

What does it mean by a type two error. Some help with the question. Thanks

• Why is it necessary to protect aniline as acetanilide before nitration?

I know u need to but why. Thanks

• Why are amine substituents ortho, para directing and carboxylic acid substituents m-directing?

I understand it is because of resonance and whether or not the the substituent group is electron donating/withdrawing. How do u explain this further. Thanks

• How would you synthesis p-bromoaniline from nitrobenzene?

Not sure on how i would do this. Some help would be good. thanks

• How do you use the laplace transform to sovle this equation?

intergral from 0 to t f(r)f(t-r)dr=6t^3

How do u do this question. Some steps would be great. Thanks

• Using a 95% confidence interval how would you compare two sets of data?

given

n mean std dev

115 18 7.8

220 6.5 3.4

how do you do this. thanks

• Using a 95% confidence interval to describe the difference in exposures?

GIven:

n mean std dev

115 18.0 7.8

220 6.5 3.4

• What is the distribution of the height of the wall and the probability that the height differs of height 200cm?

by more than 1cm

A wall is made from precast blocks. Standard 20cm blocks are 19.5cm high to allow for a 0.5cm layer of mortar. In practice, the height of a block plus mortar row varies according to a Normal Distribution with mean 20.0 cm and standard deviation 0.25cm. Heights of successive rows are independent. The wall has 10 rows.

Some help with this question would be really good especially in relation to what the question is asking. Thanks

• Laplace transformation of the function cosh^2 (t)?

Some help. Thanks

• Laplace transformations/equations?

let ℒ{y(t)} = Y(s). Find Y(s) if y" + 4y = tH(t-3) ; y(0) = y'(0) = 0

Not sure how i am spose to solve this question. Some steps would be good. Thanks

• Laplace transformation of a function?

(t^3)/24 -3t + 2

I need some steps that show me how to solve this type of question. Thanks

• Spectroscopy - Regions of the NMR spectrum?

In which region of an 1H MNR spectrum would you expect to see the peak(s) corresponding to methylene protons attached to the carbonyl of an ester?

a. 3.5 - 4.5 ppm

b. 1.0 - 2.0 ppm

c. 0.0 - 1.0 ppm

d. 3.0 - 4.0 ppm

e. 1.5 - 2.5 ppm

How do you do this type of question. the only one i can eliminate is c as it makes no sense. is this something i am spose to find in a table? No picture was provide with the question. Can someone explain it. Thanks

• X is a continuous random variable with probability density function f(x) = 0.5x, 0 < x < 2.?

What is the value of the number, m, for which P(X < m) = 0.5?

a. 1.2212

b. 1.5000

c. 1.1250

d. 1.7321

e. 1.4142

Can somebody help me with this question. Thanks

• Probability drawing marbles out of a bag without replacement?

I draw three marbles from a bag containing 6 red marbles, 10 blue marbles and 14 green marbles, all indistinguishable except for their colour. The marbles are drawn WITH replacement, and the bag is properly shaken after each marble is returned. Let X be the number of green marbles I obtain. Does X have a Binomial distribution?

a. No, because there are three, not two, categories of results.

b. Yes

c. No, because the selections of marbles are not independent

d. No, because the prob of a green marble changes from draw to draw

e. No, because the number of trials is not fixed

I have eliminated a and c. I am thinking the answer is b. can somebody help me out. Thanks