Find the current in the bulb R1?

In the circuit of the figure , each resistor represents a light bulb. Let R1=R2=R3=R4= 4.51 ohms and let the EMF be 9.10 V.


A) Find the current in the bulb R1.


B) Find the current in the bulb R2


C) Find the current in the bulb R3


D) Find the current in the bulb R4

Find the current in the bulb R1?
______________________________





R1= R2 = R3 = R4=r = 4.51 ohm





R2 , R3 and R4 are parallel,their resultant will be r/3 or (4.51/3) ohm





R1 is in series with r/3





Net resistance in the circuit =Rnet=r+ r/3 =4r/3=4*4.51/3





Rnet = 6.0133 ohm





Total current = I tot =V/Rnet =9.1/6.0133=1.513 A





The current in the bulb R1 = total current =1.513 A





A) The current in the bulb R1 =1.513 A


____________________________


The current in the bulb R2= the current in the bulb R3= the current in the bulb R4=(1/3) the current in the bulb R1=1.513/3 =0.5044 A





B) the current in the bulb R2 =0.5044 A





C) the current in the bulb R3=0.5044 A





D) the current in the bulb R4=0.5044 A





_____________________________________
Reply:If they're in series, then you add up the resistance of each for total resistance:





Total is 18.04 ohms





A) I = V/R = 9.10 volts /18.04 ohms(hot resistance) = 0.504 amps


B) 0.504 amps


C) 0.504 amps


D) 0.504 amps








Each bulb will be W = IV = 0.504 amps (9.10volts) = 4.59 watts








Total Power ~ 18.4 watts











If they're in parallel, then:





Rtotal = 1/(1/R1) + (1/R2) + (1/R3) + (1/R4)





= 1/ 4(1/4.51ohms)





= 1/ 0.887 ohms





= 1.1275 ohms





Vtotal = V(R1) + V(R2) + V(R3) + V(R4)





Vtotal = 4V(R1)





(1/4)Vtotal = V(R1)





(1/4) 9.1 volts = 2.275 volts





A) I at R1 = V(R1)/Rtotal = 2.275 volts/1.1275 ohms = 2.02 amps


B) I at R2 = V(R2) / Rtotal = 2.02 amps


C) = 2.02 amps


D) = 2.02 amps





Each bulb will be W = IV = 2.02 amps(2.275 volts) = 4.59 watts





Total Power ~ 18.4 watts