OAR OAR Mechanical Comprehension: Electricity Questions and Answers 3

Question 1

What is the total resistance of a 6-ohm and a 3-ohm resistor connected in parallel?

Accepted Answer

2 ohms

Answer

Using the parallel formula (1/Rt = 1/R1 + 1/R2), 1/6 + 1/3 = 1/2, so Rt equals 2 ohms.

Question 2

Which component opposes changes in current flow in a circuit?

Accepted Answer

Inductor

Answer

An inductor opposes changes in current by generating a back-EMF proportional to the rate of current change.

Question 3

If the voltage across a circuit is doubled while resistance stays the same, what happens to the current?

Accepted Answer

It doubles

Answer

According to Ohm's law (I = V/R), doubling the voltage with constant resistance doubles the current.

Question 4

What does a fuse do in an electrical circuit?

Accepted Answer

Breaks the circuit when current exceeds a safe level

Answer

A fuse contains a metal wire that melts and breaks the circuit when current exceeds its rated value.

Question 5

In a DC circuit, electrons flow from which terminal to which?

Accepted Answer

Negative to positive

Answer

Electrons carry negative charge and are attracted toward the positive terminal, flowing from negative to positive.

OAR Test Practice Test