Problem Solving Strategies

@AnnamalaiSriram :)

1 hour later…

5:47 AM

@HrishabhNayal yes it does. The dependence on the reflectivity with angle is described by the Fresnel equations:

Fresnel equations

The Fresnel equations (or Fresnel coefficients) describe the reflection and transmission of light (or electromagnetic radiation in general) when incident on an interface between different optical media. They were deduced by Augustin-Jean Fresnel () who was the first to understand that light is a transverse wave, even though no one realized that the "vibrations" of the wave were electric and magnetic fields. For the first time, polarization could be understood quantitatively, as Fresnel's equations correctly predicted the differing behaviour of waves of the s and p polarizations incident upon a...

6:01 AM

@JohnRennie ok what about just pure reflection?

6:18 AM

@HrishabhNayal when you say "pure reflection" are you thinking about metal surfaces where all the light is reflected?

@JohnRennie yes

mirrors would be different story IG

If all the light is reflected then all the light is reflected i.e. the reflection coefficient is always 100%

what about like real life cases , when some light is absorbed?

will that amount always be a constant , irrespective of angle?

@JohnRennie

I'm not sure to be honest. I would guess the reflectivity increases as the angle to the normal increases i.e. normal incidence has the lowest reflectivity.

This is certainly the case for x-rays reflecting off metals.

@JohnRennie ok

also I had some computer questions

6:25 AM

Yes ... ?

would you mind coming in this room:

Room for Hrishabh Nayal and John Rennie

3 hours later…

9:29 AM

Hello @JohnRennie sir

What mathematics course are required to understand Boltzmann distribution curve

satan 29

youll need to find non trivial zeroes of the zeta function.

That will take you a while ...

@PrateekMourya just regular calculus is all you need to understand the Boltzmann distribution.

satan 29

@JohnRennie XD

Is calculus from jee preparation of enough?

@PrateekMourya yes

10:10 AM

Sir i successfully installed windows 7

But the evil of problem did not ended here

Now it is not showing wifi options

Like it doesn't show if i have wifi device

It probably means you need the driver for your wifi card. Because Windows 7 is quite old it doesn't have drivers for everything like Win10 does.

Give me a moment to check Dell's support page for your laptop.

Go to this page

Change the operating system to Windows 7 and the type to Network:

It shows drivers for three network cards.

You need to figure out which network card you have, and you do this using the device manager.

If you open Device Manager and go to Other devices you'll probably see several unknown devices listed there. One of those will be the wifi card.

10:27 AM

There are three other devices

Network controller Ethernet controller and

USB 2.0CRW

@PrateekMourya It's probably the "Network controller"

Right click it and choose Properties, then go to the Details tab.

Then from the Property list choose Hardware IDs. You'll see something like this:

The DEV_xxxx text tells you what device it is. What does that text say?

Sir how long are you available here?

I need to go out now for about 20 minutes. But then I'll be back for about an hour.

10:38 AM

11:00 AM

@PrateekMourya hi, I'm back

11:17 AM

Wait

Hi :-)

Have you checked in Device Manager?

In the Property drop down choose Hardware IDs and show me what it says.

OK, that's a Qualcomm QCA9565 / AR9565 Wireless Network Adapter

So let's have a look on the Dell support page

Hmm, I can't tell which of the Dell drives it is ...

satan 29

11:30 AM

@JohnRennie hi, I think I just came up with a proof of gauss theorem for any surface!!

@satan29 give me a moment while I struggle with Dell's web site ...

@PrateekMourya did you install 64 bit or 32 bit Windows 7?

Try this driver and see if it works.

Is this definitely your laptop?

Sir once it is downloaded i will not be able to continue since my father is using it but anyway thanks i will continue tomorrow

OK :-)

2 hours later…

2:05 PM

Sir it says installation failed

@JohnRennie sir

Did it give a reason why the install failed?