Question

A wall consists of alternating blocks with a length d and coefficients of thermal conductivity k1 and k2. The cross sectional areas of the blocks are the same. Then equivalent thermal conductivity, of wall is: (t1 and t2 are temperature at two sides of wall)

Answer 1

The ground state energy of hydrogen atom is 13.6 electron volt if an electron makes a transition from an energy level -1.5 one electron volt to -3.4 electron volt then calculate the wavelength of the spectral line emitted and name of the series of hydrogen spectrum to visit england