Which is lighter ??

 This question was asked on  Koun Banega Karodpati program. 

Question

In mirrors of James Webb Telescope which light weight element is used   ?? 

1.   Berilium

2.  Silicon

3.  Lithium

4.  Titanium

Answer

As a science student,  I know Lithium is comparatively lighter than all the others given in options. 

But answer was    BERILIUM     !!! 

I wondered how   ?? 

I searched the web. 

James web telescope is a space based infrared telescope. 

Though Lithium is light weight metal,  it is highly reactive and have structural deformities while working on low temperature of space. 

That's why Berilium is chosen over Lithium to make the mirrors of James web telescope as it fulfills the required conditions.

Largest riverine islands in the world

 I have listed down the largest riverine islands by their country and their respective river.

1.  Marazo     ,       Brazil      ,   Amazon 

2.  Bananal    ,   Brazil      ,     Araguaia 

3. Ilha do  tupinambarana ,  Brazil ,  Amazon 

4.  Chongqing  ,   China ,  Yangtze 

5.   Velky Zitny ostrov ,  Slovakia , Danube 

6.  Majuli ,  India , Brahmaputra 

7.   Shri Rangam,     India ,    Kaveri

8.  Zavikon island ,   Canada ,  St  Lawrence 

Which is the most colourful flag in the world ??

 Flags are more than just a piece of cloth !!!

They represent country's value, history and identity.

I am listing out the colourful flags of different countries and the number of colours they have.

1.   Belize        ,       12

2.   South Africa  ,    6

3.   Portugal   ,      6

4.    Dominica   ,    6

5.     Central African  Republic ,   5

6.   Seychelles ,   5

7.    India  ,   4

8.   Andorra  ,   4

9.   Vanautu  ,    4

10.   Mauritius ,   4

Countries accepting UPI payments outside India

 UPI (  Unified Payments Interface    )  is a digital payment system.

It lets you send or receive money instantly using apps like  BHIM ,  PhonePay , GooglePay  or  Paytm.

UPI is not just for India.   It is spreading worldwide.

Here is the list of countries accepting UPI payments  -----

1.    Bhutan 

2.   France 

3.  Mauritius 

4.  Nepal

5.   Singapore 

6.   Sri Lanka 

7.   UAE 

8.   Cyprus 

9.  Qatar 

10.  Malaysia 

Why is it difficult to balance a stationary two Wheeler?

 Stationary objects experience only gravitational force.

Such objects can be balanced only when -----

 The line connecting the center of gravity of the object towards the earth

Touches the ground at a point within the base of the object.

If the base are is large, like in the case of a 4 wheeler, 

Slight deviations due to external forces such as wind, will not push this point out of the base.

So, it is easy to balance such vehicles.

In the case of two wheelers, the base is very narrow.

Hence any slight disturbances, will push the line of action outside the base area. 

Leading to vehicle becoming imbalanced.