More about resistance

Question 1

What is the equation and rule for total pd across resistors in series?

Answer 1

v = v1 + v2 = IR1 + IR2

total pd is equal to the sum of individual pds

Question 2

What is the rule for total resistance in series?

Answer 2

r = v / i = ( IR1 + IR2) / I = R1 + R2

total resistance is equal to the sum of individual resistances

Question 3

What is the rule for resistors in parallel?

Answer 3

resistors in parallel have the same pd

the current through a parallel combination of resistors is equal to the sum of the individual current

Question 4

What is the equation for total current through the combination in parallel?

Answer 4

I = I1 + I2 = V / R2 + V /R1

Question 5

What is the equation for total resistance in parallel?

Answer 5

1 / R = 1 / R1 + 1 / R2…

Question 6

What causes heating in an electric circuit?

Answer 6

due to the resistance

charge carriers collide with the positive ions of the conduction material

there is a net transfer of energy from the charge carriers to the positive ions due to these collisions

after a charge carrier loses KE in such a collision, the force due to the pd across the material accelerates it until it collides with another positive ion

Question 7

How is power supplied to the component calculated?

Answer 7

p = IV = I^2R = V^2 / R

Question 8

How is the rate of heat transfer calculated?

Answer 8

= I^2R

if the component is at a constant temperature, heat transfer to the surrounding takes place at the same rate