Engineering Pre-Major Year: Current and Resistance

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What quantity does Amp represent in electric circuits?

Electromotive force

Voltage

Resistance

Current (correct)

What is the relationship between voltage, current, and resistance in an electric circuit?

Current is directly proportional to voltage and resistance

Voltage is inversely proportional to current and resistance

Voltage is directly proportional to current and inversely proportional to resistance (correct)

Resistance is directly proportional to current and voltage

What type of circuit element is a voltage source?

Active element (correct)

Dependent source

Passive element

Independent source

What is the main difference between an open circuit and a closed circuit?

The presence or absence of a conductive path Signup and view all the answers

What type of circuit is characterized by an unintended path of low resistance?

Short circuit Signup and view all the answers

What is the purpose of passive elements in electric circuits?

To use or dissipate electrical energy Signup and view all the answers

What is the unit of resistivity?

V/mA Signup and view all the answers

What is the relationship between current density and electric field?

J = σE Signup and view all the answers

What is the inverse of resistivity?

Conductivity Signup and view all the answers

What type of materials obey Ohm's Law?

Linear materials Signup and view all the answers

What is the measure of how much a conductor resists the flow of charges?

Resistance Signup and view all the answers

What is the relationship between resistivity and current density?

ρ = J/E Signup and view all the answers

What is the relationship between the temperature coefficient of resistance and the nature of the material?

It depends on the material's nature. Signup and view all the answers

What is the formula for finding the resistance at a certain temperature, TF?

R₂ = R₁(1 + α₁ΔT) Signup and view all the answers

What is the unit of the temperature coefficient of resistance, α?

1/°C Signup and view all the answers

If the temperature coefficient of resistance, α, is given in terms of %/°C, how would you convert it to 1/°C?

α₁ = α₀ / 100 Signup and view all the answers

What is the relationship between the initial resistance, R₁, and the final resistance, R₂, at a certain temperature, TF?

R₂ = R₁(1 + α₁ΔT) Signup and view all the answers

What is the resistance of an electromagnet winding of copper at 20°C if its resistance at 200°C is 30Ω?

15Ω Signup and view all the answers