Question Discussion & Solution

CONCEPT:

• Power is the ability to bend light and it is equal to the reciprocal of the focal length of the lens/mirror in meters.

Power (P) = 1/f

Where f is the focal length of the lens/mirror.

EXPLANATION:

As explained above, Dioptre is a unit of measurement of the optical power of a lens or curved mirror, which is equal to the reciprocal of the focal length measured in metres.

And since the S.I unit of the focal length is the meter (m).

So the S.I unit of power = 1/(SI unit of focal length) = m-1 = Dioptre (D).

1 m-1 = 1 D

Concept:

Meaning of i++:

First, we read the i than after reading the value of i we are going to increment i this is nothing but post-increment.

Meaning of ++i: 

First, we increment i than we read the value of I, this is nothing but pre-increment:

Examine code:

int main( )
{
int i = 10;
int C = i++;   // assign i to C therefore C = 10 after assigning increment i by 1
printf("i = %d, C =  %d", i, C);
return 0;
}

Output:

i = 11, C =  10

Therefore value of i to be assigned to C, and then I to be incremented by 1

The correct answer is Vitamin A.

Key Points 

• Night blindness is the inability to see well at night or in poor lighting conditions. 
• Night blindness is also called nyctalopia.
• Night blindness is often caused by Vitamin A deficiency.
• Night blindness is also caused by nearsightedness or cataracts.
• Foods that provide Vitamin A are carrots, sweet potatoes, eggs, milk, milk products, etc. 

Additional Information 

The correct answer is Rani Kanakwati.

• Rani Kanakwati built the Jagat Shiromani temple of Amer.

Key Points

• Jagat Shiromani temple of Amer 
  • Jagat Shiromani is a Hindu temple situated in Amer, Jaipur.
  • This temple is dedicated to the Hindu gods Krishna and Vishnu.
  • It was constructed between 1599-1608 AD by Queen Kanakwati, who was the wife of King Man Singh I.
  • The temple was built in the memory of their son Jagat Singh.

​Additional Information 

• Other famous temples of Jaipur
  • ​Birla Mandir
  • Garh Ganesh
  • Shila Devi
  •  Galta Ji Temple
  • Govind Devji Temple
  • Moti Dungri Temple 

Bleaching powder:

• Calcium hypochlorite is known as bleaching powder.​
• It is a pale yellowish powder having a strong smell of chlorine.
• It is soluble in cold water.
• Bleaching powder reacts with dilute acids to produce chlorine.
• When bleaching powder is treated with an excess of a dilute, all the chlorine present in it is liberated.
• It is used in bleaching clothes in the laundry due to its oxidizing property.

Formula- CaOCl₂ 

Additional Information

• Washing powder: The chemical name of washing soda is Sodium carbonate Decahydrate and the chemical formulae is Na_2​CO3​.10H_2​O.
• Baking powder: Sodium hydrogen carbonate is the chemical term for the baking powder with chemical formulae NaHCO₃.
• Soda ash: Anhydrous Sodium carbonate is known as Soda ash with chemical formulae Na₂CO₃.