Q 1.3) Check that the ratio ke2/G memp is dimensionless. Lookup a Table of Physical Constants and determine the value of this ratio. What does the ratio signify?

 
The given ratio is ke2Gmemp Where G= Gravitational constant. Its unit is Nm2kg2
me and mp = Masses of electron and proton and their unit is kg.
e = Electric charge. Its unit is C.
k=14πε0 and its unit is Nm2C2
Therefore, the unit of the given ratio
ke2Gmemp=[Nm2C2][C2][Nm2kg2][kg][kg]=M0L0T0
Hence, the given ratio is dimensionless. WAR
e=1.6×1019CG=6.67×1011Nm2kg2me=9.1×1031kgmp=1.66×1027kg
Hence, the numerical value of the given ratio is
ke2Gmemp=9×109×(1.6×1019)26.67×1011×9.1×1031×1.67×10272.3×1039
This is the ratio of electric force to the gravitational force between a proton and an electron, keeping distance between them constant.