KNOW WHY DO MOBILE NUMBERS HAVE EXACTLY 10 DIGITS !

We have been using mobile phones for a long time, one thing that we have been noticing is that mobile number contains 10 digits. Have you ever thought about why there are only 10 digits in a mobile number, why not 9 or 11? Let's understand this in the following article.

The number of digits in a mobile number depends primarily on the population of a country. This is because the number of mobile numbers available should obviously outnumber the number of users. The current population of India is 1,350,403,177.So, we have already surpassed the 10 digit population at this moment. There is no scope for making mobile numbers less than 10 digits.

It is always assumed that each and every citizen will possess a mobile phone. Therefore, India settled for 10 digit numbers under the Government’s National Numbering Plan (NNP). By keeping 10 digit numbers, we get a combination of 1,000 crore numbers. Here is how,

It is all about permutations and combinations,

How many single-digit numbers do we know? 10.

Thus, if phone numbers were to have 2 digits, how many different number combinations would be available? 10 x 10 = 100.

In the same fashion, if phone numbers were to have 9 digits, this would only satisfy 1,000 million (100 crore) subscribers.

Hence, the 10-digit mobile number.

10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 = 10,00,00,00,000 = 10 billion (1000 crore) subscribers!

This offers us 10 billion (1000 crore) different combinations.

The Department of Telecommunication had implemented this 10 digits mobile number in 2003 for the next 30 years but when it crossed 11 years the quota is at the final stage. The officials confirm that due to the high demand, the need for 11 combinations will arise within 2 or 3 years.

This is to say that India might get an 11 or 12 digit mobile number in the future. Let’s see. Thank you for reading the article.

KNOW WHY ROCKETS ARE LAUNCHED FROM SRIHARIKOTA !!

Whenever we hear the news of a rocket launch in India, one thing is common among them-all of them are launched from Sriharikota, AP. Have you ever imagined why rockets are launched from Sriharikota? Let's discuss this in the following article.

It was in 1969, Sriharikota, which houses the Satish Dhawan Space Centre (SDSC) or Sriharikota High Altitude Range (SHAR), was chosen as a satellite launching station. Several factors were taken into consideration while selecting Sriharikota as India's ideal satellite launchpad.

1.) Equatorial Equation: Most satellites orbit the earth around the equator, and Southern India is closer to the equator than other regions of the country. So launching from here saves expensive rocket fuel.

2.) Near the Sea: Sriharikota is surrounded by the Bay of Bengal and Pulicat lake. Once a rocket ignites and lifts off, there's not much control over it even if it deviates from its set path or does not follow its trajectory. If such a situation however occurs, a destruct command is given out. This command destroys or completely disintegrates the rocket and makes it fall into the sea. Places near the sea or desert, with no habitation, are chosen as a safety measure.

3.) Stable geographical platform: One of the major criteria for the selection of launchpad is a stable platform which means soil should be strong, with the hard rock below it. This is done to withstand intense vibrations produced during the rocket launch. Sriharikota meets this criterion making it an ideal launchpad.

4.) Velocity: Since the earth rotates from west to east, in order to use the rotation as a boost and to not rather spend precious fuel against it, the rocket needs to launch eastwards. So launching a satellite in an eastward direction, as close to the equator as possible, gives the launch vehicle, or the space equivalent of the discus, extra thrust. This, in turn, saves precious rocket fuel.

While these are some of the most important criteria that need to be considered while deciding the location of the launchpad, several other smaller considerations, like the geomagnetic fields and climate, that also play a role in the decision-making.

Over the years, ISRO has had 60 tech-development launches, 87 Indian spacecraft launches, 8 student satellite launches, 2 re-entry missions, and 180 foreign satellites- from 23 countries- lift-offs from Sriharikota.

Thank you for reading the article.

KNOW WHY AIRPLANES CAN'T FLY IN SPACE !

Airplanes can easily fly in the sky but one question that might come to your mind is why it can't reach space? In this article, we will discuss the reasons that are stopping airplanes to fly in space.

1.) Earth's gravity: In order to reach space, the airplane needs to escape the earth's gravity. This requires a minimum speed of Mach 33 (25,000 mph). The current world record for the fastest plane is only Mach 6.7 (5,140 mph).

 2.) Less/ No oxygen: As the altitude rises the amount of oxygen reduces. The reduction in oxygen leads to difficulty in combustion. This leads to a reduction in thrust.

3.) No lift: At a higher altitude, the air isn’t dense enough to support a large airplane. It may produce some lift, but it won’t be enough to prevent the airplane from falling down to a lower altitude where the air is denser. In space, of course, there is no air whatsoever. Without the presence of air, neither a large airplane nor a small airplane will produce lift. There’s simply no air to travel over and under an airplane’s wings in space, which is the main reason airplanes can’t fly in space.

On the other hand, rockets do not need outside air to lift them. 

Rockets use some of the basic laws of nature. One of these is called Newton's third law. It says for every action there is an equal and opposite reaction. Most rockets use high-speed gases. These gases come out of the burning rocket fuel. These gases push the rockets up and away from Earth. They push the rocket up into space where there is no air. Remember: rockets do not need air to lift them up as planes do. Thanks for reading the article.