Conservation of Energy in Circuits

Question 1

what is the conservation of energy

Answer 1

the principle that energy cannot be created or destroyed, only transferred

Question 2

how does the conservation of energy apply in a circuit

Answer 2

the energy converted by the battery has to equal the energy dissipated in all of of the components in the circuit

Question 3

if you have three resistors in a circuit with one battery, with the resistors having their own pd, how would you write an equation showing the conservation of energy in the circuit with their charge

Answer 3

• Qe = QV1 + QV2 + QV3

- or, e = V1 + V2 + V3

Question 4

what cold you replace the Vs in the equation with and how would it then look

Answer 4

• V = IR

- e = IR1 + IR2 + IR3

Question 5

what symbol would you use to simplify the summation of IRs

Answer 5

e = sigma IR

Question 6

if the emf of the battery was 24V and the first, second and third resistors had resistance of 2, 4 and 6, with a current of 2A flowing through the circuit, what would the equation look like if 1 C of charge were present

Answer 6

• 24 x 1 = 1V1 + 1V2 + 1V3
• 24 = sigma IR
• 24 = (2x2) + (2x4) + (2x6)
• 24 = 4 + 8 + 12 (J)