0
votes
0answers
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 ...
1
vote
2answers
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 ...
0
votes
2answers
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 ...
0
votes
2answers
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 ...
0
votes
1answer
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 ...
2
votes
3answers
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 ...
0
votes
0answers
39 views

Experimental information: is momentum conserved?

Could I say that it is conserved during the time, or instead there is a slight decrease?
0
votes
1answer
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 ...
-6
votes
3answers
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 M√ľnchhausen allegedly pulled himself and the horse on ...
2
votes
6answers
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 ...
0
votes
2answers
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 ...
3
votes
1answer
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 ...
0
votes
1answer
174 views

What could I test for in a guillotine? [closed]

I'm doing a school assignment project and I need to investigate something of my choice. I was thinking of doing something about how the height and angle the blade of a guillotine is dropped from ...
3
votes
1answer
425 views

How to set up a very simple experiment in optics?

This might come across as a very rudimentary question. My fundamentals of Optics are weak. In the optics chapter of my physics text book I saw diagrams each depicting an object on the left and a lens ...