Paper 2 Current Electricity Fundamentals Drills

Q1 Charge flow and power

A heater operates at $12.0\mathrm{V}$ with current $3.50\mathrm{A}$ for $4.0\min$.

1. Calculate charge transferred. [2]
2. Calculate energy transferred. [2]
3. Calculate resistance of the heater. [2]

Q2 Resistivity

A wire of length $1.80\mathrm{m}$ and cross-sectional area $2.5\times 10^{-7}{\mathrm{m}}^2$ has resistance $4.6\Omega$.

1. Calculate the resistivity. [3]
2. State what happens to resistance if the wire is doubled in length. [1]
3. Explain why resistivity is a material property. [2]

Q3 Internal resistance

A cell of emf $1.60\mathrm{V}$ and internal resistance $0.35\Omega$ supplies current $0.80\mathrm{A}$.

1. Calculate the lost volts. [2]
2. Calculate the terminal p.d. [2]
3. Explain why terminal p.d. is less than emf. [2]