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Showing posts from June, 2018

### Why The Color Of Sky Is Blue

When the sun's light reaches the Earth's atmosphere it is scattered, or deflected, by the tiny molecules of gas (mostly nitrogen and oxygen) in the air. Because these molecules are much smaller than the wavelength of visible light, the amount of scattering depends on the wavelength.

Shorter wavelengths (violet and blue) are scattered the most strongly, so more of the blue light is scattered towards our eyes than the other colours. You might wonder why the sky doesn't actually look purple, since violet light is scattered even more strongly than blue. This is because there isn't as much violet in sunlight to start with, and our eyes are much more sensitive to blue.

The blue light that gives the sky its color, is sufficiently bright to make all the stars that we see at night disappear since the light they emit is much dimmer.

### XI Lecture No.3 | Significant Figures

Lecture Includes: XI Chapter No.1 : The Scope of Physics 1. Introduction to Significant Figures 2. Rules for counting Significant Figures 3. Examples of Significant Figures Previous Lectures: XI Lecture No.1|Introduction,History and Muslim Contribution: https://youtu.be/4tmmM3Hg5EU XI Lecture 2| Dimensions : https://youtu.be/svzZ2fUS__8

### XI Physics | Solved Numericals | Chapter No.1 | The Scope of Physics

XI Physics Chapter No.1 : The Scope of Physics

1. Find the area of rectangular plate having length (21.3 +/- 0.2 ) cm and width (9.80 +/-0.10) cm.

2.Calculate (a) the circumference of circle of radius 3.5 cm. and (b) area of circle of radius 4.65 cm.

3.Prove that S=vit + 1/2 at^2 is correct dimensionally.

4.Suppose displace of a particle is related to a time according to a expression S= ct^3. what are the dimensions of constant c ?

5.Estimate the number of liters of gasoline used by all Pakistan's car each year.

### XI Lecture 2| Dimensions

Chapter No.1 : The Scope of Physics Topic :Dimension
Lecture contents: 1. Definition of Dimension 2.Dimension of Physical Quantities 3.Equation verification by using dimensions and Exam Questions

### XI Lecture No.1 The Scope of Physics

Chapter No.1 : The Scope of Physics Lecture contains; 1. Introduction and definition of Physics 2. Brief History of Physics 3. Contribution of Islamic World towards Science

### XII Lecture No.1 | Heat, Temperature and Thermometric properties

Chapter No.11 : Heat 1.Heat 2.Temperature 3.Thermometric Properties