Quiz 11

Question 1

The total resistance of any number of parallel resistances, all having the same value, is equal to the value of any one of the resistors divided by the total number of resistors.

True or False?

Answer 1

True

Question 2

Adding additional resistors in parallel with those resistors already existing in a parallel connected circuit will always increase the total resistance.

True or False?

Answer 2

False

Adding additional resistors in parallel with those resistors already existing in a parallel connected circuit will always decrease the total resistance.

Question 3

A circuit contains five 180-ohm resistors in parallel. What is the total circuit resistance? (Use the rule for determining total resistance with resistances of equal value.)

Answer 3

36 Ω

Rₜ = R / N
= 180 / 5
= 36 Ω

Question 4

Two lamps are connected in parallel across a 120-volt source. Each lamp has an internal resistance of 96 ohms. What is the equivalent circuit resistance?

Answer 4

48 Ω

Rₜ = R / N
= 96 / 2
= 48 Ω

Question 5

State the product over sum formula for determining total resistance in parallel circuits containing two unequal resistances.

a. Rₜ = R₁² × R₂² / R₁ + R₂
b. Rₜ = √(R₁ × R₂ / R₁ + R₂)
c. Rₜ = R₁ + R₂ / R₁ × R₂
d. Rₜ = R₁ × R₂ / R₁ + R₂

Answer 5

d. Rₜ = R₁ × R₂ / R₁ + R₂

Question 6

Use the product-sum method to solve for total resistance in a circuit containing one 25-ohm and one 15-ohm resistor. (Round the FINAL answer to three decimal places.)

Answer 6

9.375 Ω

Rₜ = R₁ × R₂ / R₁ + R₂
= (25 × 15) / (25 + 15)
= 9.375 Ω

Question 7

Use a variation of the equal-resistance rule to solve for the equivalent resistance in the circuit. (Round the FINAL answer to one decimal place.)

Answer 7

7.2 Ω