Recent content by Clari

The expenses of customers follows a normal distribution with mean equals to $428, and standard deviation equals to $100. A customer spending $600 or more will receive a gift. If the probability of the shopping centre giving out gifts is at least 0.99, find the smallest no. of customers visiting...

A student wishes to light a lamp rated 12V, yet he has only a 2V rms a.c supply with variable frequency. So he attempts to step up the voltage by means of a transformer. Given Ns:Np = 6:1, resistance in the primary circuit is 70 ohm, inductance of primary coil is 0.3H, frequency f is 50Hz a.)...

Thanks for your help,Tide and HallsofIvy ^-^

Hello, i found one question really difficult and I can't solve it. Please help. Six hens are observed over a period of 20 days and the number of eggs laid each day is summarised in the following table: No. of eggs: 3 4 5 6 No. of days: 2 2 10 6 This can be considered as a...

Hello! I am doing some questions about sound waves for my homework assignment and have some problem in one of them. Assuming that it radiates sound uniformly, find the sound power from a motor car whose sound level at a distance of 7.5m is 87dB. Here are my steps: I = sound intensity, I_0 =...

so because the carbocation intermediate of tertiary ROH is more stable, so the presence of a little amount of water does not affect the reaction much. Am I right? :rolleyes:

Hello BobG, i can figure it out now. Thank you very much. Your help is greatly appreciated. :approve: well, i have also tried the alternative method before but i don't know why the two voltages have to subtracted from each other. :smile:

In the substitution of ROH to RX, dry HCl and anhydrous ZnCl2 catalysts are used for primary and secondary alkanol. Why it is fine to use concentrated HCl and ZnCl2 for tertiary alkanol, that is to say, with small amounts of water present?

hi there, i have two questions concerning operational amplifier which i can't figure out. i have tried them for hours, and finally get on a bit, yet i am not sure whether i have the answer right. :( 1a. What is the value of the feedback resistance in figure 1? My ans: V_out/ V_in = 1+...

i see...Thanks GCT, your help is appreciated. ^-^

Hi there! i feel confused at a question in my homework: Predict whether the following reactions can occur at low temperature a) CH2CH2 + (H+) b) CH3Br + RNH2 c) CH4 + HCl d) CH£Br + (CN-) I don't know what should be concerned, please help me. :rolleyes:

I think your answers are right, while those given by my teacher are wrong, so i believe i know how to sort it out now. ^^ Thank you very much! :smile: To geosonel, i haven't learned anything about the RLC circuit in parallel in fact, so i know nothing about complex representations. What is...

Hello olderdan and geosonel, thank you for your help. I realize I have treated the problem wrongly. However, when I follow your method, i get the total current to be 4.9095 ohm; and the answer given is 0.8865A. Yet, the other two answers are 0.8642A and 0.1964A respectively, which do not add up...

A coil of self-inductance 0.7H is joined in parallel with a non-inductive resistance of 50 ohm. Calculate the total current, the current throught the wattless and power components when connected to a supply of 200V at a frequency of 50Hz. Here is my steps: Impedance Z= root [ 50^2 +...

Hi there! I have some problems in this topic...real difficult to me. ^-^ A 1(miu)F capacitor is connected in series with a coil of R=50(ohm) and L=49mH and an a.c. ammeter. A current of r.m.s. value 0.03A and f=500Hz is passes through the combination. What is the peak p.d. across the...