Why AC circuit was chosen over DC?

George Westinghouse was the scientist who discovered or formulated the idea of power transmission via AC over DC to which he had following stances,

1. While transmitting power via AC source less amount of current is transmitted over high voltage which ultimately leads to less power wastage in the form of heat or in the case of transmission failure

2. Small size of motor was also a factor which was included in it as for a DC source the winding on the motor i very heavy which ultimately increase the centripetal force and great chance of motor failure.

On the contrary less heat consumption and less chance of motor failure was the key factor in the acceptance of AC circuit as the method of power supply.

Is Rutherford's experiment actually his?

 As we study Rutherford gold foil scattering experiment we come to know about the structure of the atom,

But is the Gold foil experiment really was the idea of Rutherford❓

An article was published in Royal society 1909A, Volume 82, Page 495-500, 

By H Geiger and E Mardsen in which they described the experiment performed by them in which they bombarded the alpha particle on a metal sheet and they observed that 1 out of 8000 are back scattered.

This was quite a surprise as alpha particle are heavy particle and that too moving with such a great velocity will ultimately result in much greater Momentum and such particle is back scattered by tiny particle at rest which was itself a surprise.

At the conclusion they said that bouncing back of alpha particle is a great surprise but no conclusion can be concieved out of it.

Later on in 1911 Rutherford performed the same experiment and reached to a  conclusion that at a very small area a large group of mass is concentrated (Nucleus) which ultimately results in bouncing back of alpha particle.

Why diamond is so costly?

Diamond is just an allotrope of carbon still so expensive because of the art work performed on it,

Whenever any light enters a piece of material it tries to travel through it or cross it but some of them suffer total internal reflection (TIR) when the incident light crosses the mark of critical angle,

According to this the light is not able to come out of the material and it suffers multiple reflection within it's boundaries.

For a well crafted diamond the value of critical angle is 22.4 

Why the pencil looks shifted when kept in a glass of water? 🤔

 

Whenever light travels from one medium to another it changes it's angle and thus we see that the object is shifted 

The relation of light travelling from one medium to another is given by snell's law i.e.

 nA Sinθ A = nB Sinθ B