# Tagged Questions

25 views

### Regarding OFDM (Orthogonal Frequency Division multiplexing)? [migrated]

Ok can you please briefly explain IEEE 802.11a OFDM packet structure, 1 What is meant by symbol here? 2 What is the purpose of Packet preamble 3 What is Short training symbol and its purpose 4 ...
77 views

### The best way to cool the teapot

My professor today in the class made us a question: "Lets say we have a teapot with water in it.The water is hot.Now we want to cool the water. Will it cool faster if we put an ice cube above the ...
69 views

### Problem with horizontal projectile motion questions

I don't really understand horizontal projectile motion. Suppose I throw a ball horizontally. Given $\theta$ = 0 degrees, time = 0.5 seconds, horizontal range = 15.5 metres, the "initial horizontal ...
231 views

### Potential energy from opposing magnets repelling each other with a gap of 1 mm

I have two powerful rare earth magnets, that are separated by a distance of 1 mm. I applied energy to bring them closer to each other, hence increasing the potential energy. Now, when one of the ...
150 views

### How does temperature affect magnets?

How does an increase/decrease in temperature affect: Strength of the magnet Polarity Other changes? I have made some research and I have found that increasing the temperature turns ferromagnetic ...
156 views

### How to calculate Standing Waves in Electrical Cables?

I have a 20 metre Coaxial Cable. I send digital signals down the cable ranging from 5 KHz to 50 KHz. I have noticed a pattern in the noise ratio, an oscillating wave. I predict this is to do with ...
39 views

### Experimental information: is momentum conserved?

Could I say that it is conserved during the time, or instead there is a slight decrease?
180 views

### Magnetic field, alternated current and EMF

If I apply an alternated current to a solenoid and insert into it a smaller solenoid, I could measure the induced EMF (electromotive force) and study how it changes in relation to the frequency of ...
191 views

### Can you lift a basket up while standing inside it? [closed]

Suppose you stand in a basket and you try to pull the handles of the basket. Will you be able to lift the basket from ground? Similarly, Baron Münchhausen allegedly pulled himself and the horse on ...
7k views

### Parallel circuits - Overall resistance decreases with additional resistor [closed]

Let's say that there is a parallel circuit with two identical resistors in parallel with each other. If a third resistor, identical to the other two, is added in parallel with the first two, the ...
912 views

### Inductance - Sign convention problem…

My problem is with a circuit containing a resistor of suitable resistance $R$ and a solenoid. At time $t<0$, there was a battery that created a current in the circuit and at $t=0$, the battery is ...
390 views

### Enhance a home build spectrometer

I would like to build a home made spectrometer like it's describing here: http://coolcosmos.ipac.caltech.edu/cosmic_games/spectra/makeGrating.htm How can I improve this spectrometer? A prism from an ...