Sriman Dutta

So, the denominator should be [math]4\pi r [/math]

So, it's better to use [math]\mu_0 \mu_r [/math] for accuracy. Thanks...

Sorry, I was rather careless.

No friction in space because there's no matter in space (even if present, only in very less density). But, there's a resistance caused due to gravity----To escape the gravitational pull of a celestial object, you need to lose a bit of your energy.

Well, I see that you are using the time dilation concept; but that doesn't work well with the situation you have given. The world's fastest birds can fly at speeds not more than 320 km/h (I'm talking about the peregrine falcon). So, now the Lorentz factor becomes: sqrt(1-(320)^2/(300000)^2). That is extremely small and does not give extra time to the birds to focus.

Yes, I did so once too. Here's the explanation. For powers of two, [math] [(a+2)^2 - (a+1)^2]-[(a+1)^2 - a^2]=[a^2+4+4a-a^2-1-2a]-[a^2+1+2a-a^2]=[3+2a]-[1+2a]=3+2a-1-2a=2[/math]

Of course. And that's the reason why I said that no single subject is of utmost significance.

Hello everyone, As shown in the diagram, there is a semi-circular loop of current carrying wire, such that point P is the centre of the semi-circle and r is the radius. What shall be the magnetic flux density at the centre P? I presume that the diagram must be treated by the Ampere's Law. So, [math] B=\frac{\mu_0 I}{2\pi r}[/math]

Thanks for the response. After a while, I realized that for AM, I can use right hand thumb rule to get the direction of magnetic field. And then, I can use Fleming's left hand rule to get the direction of motion of CD. I did so and got that the wire CD shall move upwards. Here' the pic.

Hello everybody, The Ampere's Law states that the total [math]B[/math]-field generated by a conducting element of length [math]l[/math] is directly proportional to the current element [math]I[/math]. Thus, [math] Bl = \mu_0 I[/math] Where [math]\mu_0[/math] is the constant of proportionality. But, will the constant of proportionality be [math]\mu_0[/math] or [math] \mu_0 \mu_r [/math] ? These two sites use two different formulations..... http://www.electrical4u.com/biot-savart-law/ http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/magcur.html#c1

Hi, I have this question. Can anyone please explain the answer as I am unwawre of it. A current I1 carrying wire AB is placed near another long wire CD carrying current I2. I1 is perpendicular ti I2. If AB is free to move then it will move : (A) Towards left (B) Towards Right © Upwards (D) Downwards

Mathematics, perhaps... But, all subjects are equally significant for human knowledge is not restricted to any particular topic.

Its the plus-or-minus sign. You will see such signs typically in the overroot of a perfect square, and also in the quadratic equation formula.

The paradox is invalid.

Time travel. Lol!

Do you know about the golden ratio?

Yes, NaOH is generally used in analytical chemistry to determine the cations present in a solution.Another reagent used commonly is ammonium hydroxide (NH4OH).

Thanks for that advice, mordred. I think that the formula E=mc^2 shows a mass-energy equivalence, that means, if a body of mass m is suddenly due to some extreme physical conditions, changed into energy E, then E is equal to the product of m and the square of the speed of light c. The UP has used this formula for showing that all kinds of energy transfer takes place through waves.

Your formula is 100% wrong in the context.

There is, of course, a bit of risk in uploading the photos. But, that risk cannot drive you mad and make you unsocial in a social media, because there are no such things that are absolutely without risk. You may drive a car and there is a risk of a car accident ; you may be travelling on a plane and there is a risk of hijacking; you may be eating a tasty meal, but the food may be poisoned.

Firstly, constant upload of selfies is not a very positive attitude. As you have said in post #3 that you upload selfies for getting likes and comments, it eventually makes you narcissistic. It ruins your life because you always think of yourself and your life, forgetting what's going on with others. Secondly, uploading selfies makes your photos vulnerable but you can make them hide from public. So only your friends can see them and I expect that your friends are not your foes.

Indeed, life is a complex chemistry. Life is the flow of energy from one generation to another through chemical reactions. That's what life is from a chemist's point view.

Well, he might be finding his overcoat then.... And the bus number??

Good work. +1 imatfaal

While visiting a small town in the United States, I lost my overcoat in a bus. When I reported the matter to the bus company I was asked the number of the bus. Though I didn't remember the exact number I did remember that the bus number had a certain peculiarity about it. The number plate showed the bus number was a perfect square and also if the plate was turned upside-down, the number remained a perfect square. The bus company informed me that they had bus numbers from 1 to 500. From this, I got the number of the bus. Can you find out what's ths bus number? ;-)