1. Determine the voltage needed to cause a current of 4 amps in a circuit having
a resistance of 30 ohms.

The voltage needed = 120 V

Electric current (symbolized by the letter "i) is the amount of charge flowing in the conductor of each unit of time  

Can be formulated:  

Q = charge (Coulomb)  

t = time (seconds)  

The international standard unit of electric current is Coulomb/second or Ampere (A).  

Electric current is also a ratio between the voltage and the amount of resistance at the conductor.  

Can be formulated  

V = Voltage (volts)  

R = resistance (ohms)  

I=current=4 A

R=resistance=30 Ω

The voltage needed :

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