# All Questions

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### What stored charges do in a capacitor? [closed]

Why does a fan need capacitor? Capacitor is just providing charges to fan but it can be accomplished without it by directly connecting fan with electric supply. Which other appliances need capacitor?
217 views

### Does adding water on convex mirror increase its power?

What is the comparison between the power of convex lens in air and in water ? What causes the change in its focal length
1k views

### What is the difference between xrays and ultra violet rays?

Do they differ in just frequency and wavelenght ? Or there is more about it
130 views

### Why can intramedullary rod heat with MRI?

It is said, that steel rod inside body, like funeral nail, can heat while magnetic resonance imaging (MRI). But why? Isn't MRI scanner use constant magnetic field? If the heating effect is caused by ...
7k views

### What would happen if an accelerated particle collided with a person?

What would happen if an accelerated particle (like they create in the LHC) hit a person standing in its path? Would the person die? Would the particle rip a hole? Would the particle leave such a tiny ...
433 views

221 views

### Velocities of waves (such as visible light, and radio)

The speed of light in a vacuum is a constant 299,792,458 m/s. In water, it is much slower. Does this happen to such waves as radio, or X-ray? (Would say, a 3 meter wavelength travel slower in air than ...
186 views

What is the true difference between radar and sonar? My understanding is that radar uses a reflected EM wave, while sonar uses a compression (shock wave) of the material it's in. (It compresses water, ...
918 views

### Uncertainty principle in Harmonic Oscillator

In a single particle Harmonic Oscillator, suppose I prepare it in the ground state and then measure its position. From the relation connecting Total Energy, Kinetic energy and Potential I can ...
46 views

### Where can I find phase diagrams for mag-thor alloys?

Where can I find phase diagrams for Mg Th alloys? Thanks!
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1k views

### Why do rockets jettison fuel tanks? [duplicate]

I'm trying to understand why rockets have multistages releasing their fuel tanks. Say a rocket $R$ has two fuel tanks $A$ and $B$, which respectively have masses $m_a$ and $m_b$, and the mass of the ...
611 views

### Physical simulation in python [closed]

Is there a "standard" python package used to aid in physical simulations? What is the most popular? edit: perhaps I should have worded this question differently. Something more to the effect: Could ...
191 views

223 views

### Group Theoretic definition of a particle

We intuitively have a sense of what a particle means in the conventional sense. But is it possible to have a group theoretical definition of a particle, I mean in terms of irreducible representations ...
231 views

### FRW metric and its validity througout the age of the universe

Why do we think that the FRW metric should be valid throughout the entire history of the universe?
2k views

### How can we minimize the coefficient of static/kinetic friction?

Static frictional force depends on the coefficient of static friction; kinetic frictional force depends on the coefficient of kinetic friction. To minimize friction, one of two things could happen: ...