The ratio of electrostatic and gravitational force acting between electron and proton separated by a distance `5 xx 10^(-11)m`, will be (charge on electron `= 1.6 xx 10^(-19)C`, mass of electron `= 9.1 xx 10^(-31) kg`, mass of proton `= 1.6 xx 10^(-27) kg, G = 6.7 xx 10^(-11) N - m^(2)//kg^(2)`)

Calculate the ratio of electric and gravita-tional forces between two electrons. (charge of the electron (e) = 1.6 xx 10^(-19) c , mass of the electron (m) = 9.1 xx 10^(-31) kg, (1)/(4pi epsilon_(0)) = 9 xx 10^(9) Nm^(2)C^(-2) , universal gravitational constant G = 6.67 xx 10^(-11) Nm^(2) kg^(-2) )

The charge on 1 microgram (g) electron will be......(mass of an electron = 9.11 xx 10^(-31) kg)

Calculate the de-Bronglie waveelngth for electron and protonif their speed is 10^5 m s^(-1) .Given,mass of an electron =9.1 xx 10^(-31) kg ,mass of proton = 1.67 xx 10^(-27) kg and Planck's constant = 6.62 xx 10^(-34) J s .