130,462 reputation
8216357
bio website ratsauce.co.uk
location Chester, United Kingdom
age 54
visits member for 4 years, 2 months
seen 6 hours ago

Semi retired old time computer nerd who started programming on a Commodore Pet.

Since I'm also active in the Physics forum I should add that I started as a theoretical chemist, moved into solid state photochemistry and finally worked in industry as a colloid scientist. I only became a full time computer nerd in 1997.


2d
comment Why do we use microwaves in microwave oven?
I think it's good to err on the side of being nice
2d
comment Why do we use microwaves in microwave oven?
@LightnessRacesinOrbit: what seems obvious to us god-like nerds is not necessarily obvious to normals.
2d
comment Why do we use microwaves in microwave oven?
@Bhavesh: it's mainly that it's easy to produce high energy microwaves efficiently in a magnetron. The magnetron and oven are designed to be an integral number of wavelengths in size so the oven contains a standing wave. Radio waves are generally too large for this - FM wavelengths are a few metres - so it would be hard to make a radio oven powerful and efficient enough to be useful. It would be better for even heating though.
2d
comment Why do we use microwaves in microwave oven?
@LightnessRacesinOrbit: I think your criticism is a bit unfair. Radio waves are indeed used for heating in induction furnaces. Well, the heating is magnetic not electrical, but frequencies up to 400kHz are used and that's into the radio range. Induction furnaces are extremely effective at heating food, but they tend to produce a lot of electrical interference.
2d
comment How can matter reach the singularity of a black hole if time stops at the event horizon?
@QuantumForce: the key point is that in GR different observers can and do observe different things. That doesn't mean one is wrong and the other right - they are both right. For a Schwarzschild observer nothing can ever pass through the event horizon. For a free falling observer hitting the singularity takes a finite (usually very short!) time. The nothing can hit the singularity is conditionally true, and likewise conditionally false.
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comment How can matter reach the singularity of a black hole if time stops at the event horizon?
@AlfredCentauri: a few weeks back. It's actually a bit of a pain because I have to remember that my duplicate vote will now immediately close a question tagged as GR, which isn't always what I want.
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comment Laser tattoo removal
I take it back, I think there is some very interesting physics involved‌​!
2d
comment Acceleration due to Gravity: Free Fall
Also related: Will free-fall object into black hole exceed speed of light c before hitting black hole surface? and Does the pilot of a rocket ship experience an asymptotic approach to the speed of light?.
2d
comment Acceleration due to Gravity: Free Fall
possible duplicate of Will an object always fall at an infinite speed in a black hole?
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comment Laser tattoo removal
I'm voting to close this question as off-topic because it is not about physics
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comment Why do we use microwaves in microwave oven?
Related: Why do microwave ovens use radiation with such long wavelength?, though it's not a duplicate as it doesn't specifically address the question of why we don't use visible light or IR.
2d
comment How can matter reach the singularity of a black hole if time stops at the event horizon?
I've suggested what seems to me an obvious duplicate, and there are many other related posts on this site (though getting the right search terms to find them isn't trivial!). If you aren't happy that my suggested duplicate answers your question reply to this comment and I'll withdraw my clse vote.
2d
comment How does one manipulate the frequency of alternating current?
This question belongs on the Electrical Engineering Stack Exchange
2d
comment How to find the nature of an orbit knowing 2 altitudes and the time interval?
Hi Basu and welcome to the Physics SE! Please note that this is not a homework help site. Please see this Meta post on asking homework questions and this Meta post for "check my work" problems.
Mar
27
comment why the direction opposite to the heat energy of sound energy?
As it stands the question doesn't make sense. I'd guess this is a language issue. Can someone who knows the area maybe edit the question into a clearer form?
Mar
26
comment Period of small oscillations of rotational disk
As a hint: if you rotate the disk by an angle $\theta$ it stretches/compresses the spring by $r\theta$ and the resulting force is $kr\theta$. So the restoring force is proportional to diplacement, which means the system is a simple harmonic oscillator.
Mar
26
comment Period of small oscillations of rotational disk
Hi Daniel and welcome to the Physics SE! Please note that this is not a homework help site. Please see this Meta post on asking homework questions and this Meta post for "check my work" problems.
Mar
26
comment Which technique is used to measure huge astronomical distances which are in terms of billions of light years?
@KyleKanos: I almost flagged that as a duplicate, but the emphasis in this post is on the most distant objects and I'm not sure that's covered by the proposed duplicate.
Mar
26
comment How to calculate liquid pressure regardless of the gravity?
Can you clarify what you're asking? If you know $V_1$ the pressure in the ballon is just $P = nRT/V_1$, and assuming your system is in equilibrium the pressure in the liquid will be the same. The pressure in a liquid (or solid) is $P = K(V-V_0)/V_0$ where $V_0$ is the volume at zero pressure and $K$ is the bulk modulus.
Mar
26
comment Do all the emitted electron in photoelectric effect have same K.E
I have to say the question seems clear to me. However it is an exact duplicate of the one I've linked.