OAR OAR Mechanical Comprehension: Electricity 3

Question 1

In a series circuit with a 12V source and three equal 4Ω resistors, what is the voltage drop across each resistor?

Accepted Answer

4V

Answer

Total resistance is 12Ω, current is 1A, and voltage drop across each 4Ω resistor is 1A × 4Ω = 4V.

Question 2

What is the purpose of a fuse in an electrical circuit?

Accepted Answer

Protect against excessive current

Answer

A fuse contains a wire that melts and breaks the circuit when current exceeds a safe level, preventing damage.

Question 3

Two identical 10Ω resistors are connected in parallel. What is the combined resistance?

Accepted Answer

5Ω

Answer

Two identical resistors in parallel produce half the resistance of one: 10/2 = 5Ω.

Question 4

What unit measures electrical charge?

Accepted Answer

Coulomb

Answer

The coulomb (C) is the SI unit of electric charge; one ampere equals one coulomb per second.

Question 5

A transformer has 200 primary turns and 50 secondary turns. If the primary voltage is 120V, what is the secondary voltage?

Accepted Answer

30V

Answer

Voltage ratio equals turns ratio: V_s = 120 × (50/200) = 120 × 0.25 = 30V.

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