This is a fundamental constant in chemistry that represents the number of atoms or molecules in one mole of a substance. (Option 4 is correct) Its value is approximately 6.022 x 10²³, and it is denoted by the symbol "N_A". Avogadro's number is a key concept in stoichiometry. The branch of chemistry deals with the quantitative relationships between reactants and products in chemical reactions.

1. Induced current is highest when the direction of motion of the coil is perpendicular to the magnetic field.

According to the 2011 census, Jhunjhunu district had the lowest sex ratio in the age group of 0 to 6 years in Rajasthan.