A DVD is an example of Optical Disc.

Pen names have had a certain place of their own in the world of writing. Pen names are something which every writer comes across at some time in their careers.

Indian author to use a pen name Bhanu Simha is Rabindranath Tagore. He also has Gurudev, Kabiguru as his pen names.

The Rate of doing work or rate of transfer of energy is called Power.

Tea bag is what it will go in dry and come out wet, the longer it is in, the stronger the tea we will get.

The first step in photosynthesis is to split the water molecule using sun light.

In economy, the currency value depends on imports and exports, inflation, employment, interest rates, growth rate, trade deficit, performance of equity markets, foreign exchange reserves, macroeconomic policies, foreign investment inflows, banking capital, commodity prices.

The first talkie film in India was Ardeshir Irani released Alam Ara, on 14 March 1931.

Irani later produced the first south Indian talkie film Kalidas directed by H.M. Reddy released on 31 October 1931.

Given numbers are 1, 2 and 3

Factors of 1 = 1

Factors of 2 = 1, 2

Factors of 3 = 1, 2 and 3

Common factors = 1

Hence, the HCF of 1, 2 and 3 = 1.