{******************************************************* * Calculate relativistic mass and speed of an electron * * accelerated in an electron gun * * ---------------------------------------------------- * * SAMPLE RUN: * * * * Give electron gun voltage in volts: 1e6 * * * * Relativistic mass (kg) and speed (m/s): * * 2.69339461904430E-0030 2.82124894363268E+0008 * * * * ---------------------------------------------------- * * Ref.: "Problem Solving with Fortran 90 By David R. * * Brooks, Springer-Verlag New York, 1997". * * * * TPW Release By J-P Moreau, Paris. * * (www.jpmoreau.fr) * ******************************************************** !Explanations: !------------ ! ! An electron accelerated by a voltage V in an electron gun ! ! 2 2 ! acquires an energy of Ve = mc - m c, where ! 0 ! -19 ! charge on an electron e = 1.602 x 10 coulomb ! ! -31 ! rest mass m = 9.109 x 10 kg ! 0 ! 8 ! speed of light c = 2.9979 x 10 m/s ! ! The speed v of an electron of relativistic mass m (kg) is ! obtained from ! 2 ! m/m = 1 / sqrt(1 - (v/c) ) ! 0 ! !----------------------------------------------------------} Program Relativistic_Mass; Uses WinCrt1; Var rest_mass, rela_mass, { kg } voltage, { volt } speed, { m/s } e, { electron charge in coulomb } c: double; { speed of light in m/s } Begin e:=1.602e-19; c:=2.9979e8; rest_mass:=9.109e-31; writeln; write(' Give electron gun voltage in volts: '); readln(voltage); rela_mass := (voltage*e + rest_mass*c*c) / (c*c); speed := c*sqrt(1.0 - Sqr(rest_mass/rela_mass)); writeln; writeln(' Relativistic mass (kg) and speed (m/s):'); writeln(' ', rela_mass, ' ', speed); writeln; ReadKey; DoneWinCrt End. { End of file rel_mass.pas }