Dissolving 120 g of urea (mol. wt. 60) in 1000 g of water gave a solution of density 1.15 g/mL. The molarity of the solution is

Extraction of metal from the ore cassiterite involves

The maximum number of electrons that can have principal quantum number, n = 3, and spin quantum number, m_s = − 1/2 , is

The work function ( φ ) of some metals is listed below. The number of metals which will show photoelectric effect when light of 300 nm wavelength falls on the metal is