Alternator light

alt. light does not come on when ignition is turned on ; when motor starts alt. light comes on and pulses and brightens

with increase in RPMs. Battery voltage at

fast idle is only 10.5 volts when it should be approx. 13 to 14. Is this problem result of alt. voltage regulator ?

It could be. It could also be a bad battery. Have both tested. Many auto parts stores and (at least where I live) Batteries Plus will do that for free.