contestada

A resistor has a current of 2 amperes when connected to a single battery. If a second identical battery is connected in series with the first, what is the current through the resistor?

a) Still 2 amps

b) 4 amps

c)1 amp

d) no current

Respuesta :

AL2006

Ohm's law: Current = (voltage) / (resistance)

In the first situation:  2 A = V / R

After the change:  

Current = (2 · V) / R

Current = 2 · (V/R)

But each (V/R) = 2 A

So the new current is 4 A .  (choice-b)