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VICPhysicsQuick questions
Unit 1: How is energy useful to society?
Quick questions on Electric circuits and Ohm's law: VCE Physics Unit 1 Year 11
9short Q&A pairs drawn directly from our worked dot-point answer. For full context and worked exam questions, read the parent dot-point page.
What is aC vs DC?Show answer
Household electricity in Australia is alternating current (AC) at 230 V, 50 Hz. The 230 V is RMS (root mean square); the peak is about $325$ V.
What is charge $q$?Show answer
Measured in coulombs (C). The elementary charge $e = 1.6 \times 10^{-19}$ C.
What is current $I$?Show answer
Rate of flow of charge: $I = q / t$. Measured in amperes (A). 1 A = 1 C/s.
What is voltage / potential difference $V$?Show answer
Energy per unit charge between two points: $V = E / q$. Measured in volts (V). 1 V = 1 J/C.
What is resistance $R$?Show answer
Opposition to current flow. Measured in ohms ($\Omega$).
What is adding parallel resistances directly?Show answer
Use $1/R = 1/R_1 + 1/R_2$, not $R = R_1 + R_2$.
What is wrong power formula?Show answer
Use the form that matches your knowns: $P = VI$ if you know $V$ and $I$; $P = I^2 R$ if you know $I$ and $R$; $P = V^2/R$ if you know $V$ and $R$.
What is confusing voltage and current?Show answer
Voltage is across components; current is through them. In series, current is the same; in parallel, voltage is the same.
What is energy units in calorimetry context?Show answer
kWh and J both measure energy but differ by a factor of 3.6 million.