Convert the following in kilogram :
`3.34xx10^(-24) g` (mass of hydrogen molecuole

Mass of one atom of the element A is 3.9854 xx 10^(-23)g . How many atoms are contained in 1g of the element A ?

Convert the following unlike decimals to like decimals. 1.451, 7.3, 34.28

Calculate momentum of electron, if their wavelength is 1overset @ A . Given, Planck's constant h=6.625 xx 10^(-34) Js , mass of electron m=9.1 xx 10^(-31) kg.

Calculate momentum of electron, if their wavelength is 2 overset @ A . Given, Planck's constant h=6.625 xx 10^(-34) Js , mass of electron m=9.1 xx 10^(-31) kg.

Calculate the de-Broglie waveelngth of an electron of energy 400 eV.Given,lanck's constant = 6.6 xx 10^(-34) J s, mass of electron = 9.1 xx 10^(31) kg,1 eV = 1.6 xx 10^(-19) J .

Calculate the magnitude of the electrostatic force exerted by the proton on the electron in the hydrogen atom and compare it with the weight of the electron. Given that mass of electron is 9.1 xx 10^-31 kg, charge on electron is 1.6 xx 10^-19 C and radius of hydrogen atom is 0.53 overset(@)A .