WorksheetsTopic 3 SP025
Total questions: 20
Worksheet time: 10mins
What happens to the free electrons in a metal when an electric field is applied?
They stop moving entirely.
They drift slowly in the direction opposite to the field.
They move randomly without any net direction.
They accelerate indefinitely in the direction of the field.
What causes electric current to flow in a metal conductor?
The movement of positive ions in the metal lattice.
The random motion of free electrons.
The net drift of free electrons due to an applied electric field.
The vibration of atoms in the conductor.
How does the number of free electrons in a conductor affect the electric current?
More free electrons result in a higher current.
Fewer free electrons result in a higher current.
The number of free electrons does not affect the current.
Current flows regardless of the number of free electrons.
Which of the following is a characteristic of a good conductor?
High resistivity
Low resistivity
High voltage
Low voltage
How does the resistance of a conductor change if its length is doubled, while keeping all other factors constant?
The resistance remains the same.
The resistance is halved.
The resistance is doubled.
The resistance is quadrupled.
Two wires are made of the same material and have the same length, but Wire A has a larger cross-sectional area than Wire B. Which of the following is true about their resistances?
Wire A has a higher resistance than Wire B.
Wire A has a lower resistance than Wire B.
Both wires have the same resistance.
The resistance depends only on the material and not on the cross-sectional area.
What happens to the resistance of most metals as temperature increases?
It decreases because electrons move faster.
It increases because electron collisions become more frequent.
It remains constant because resistance is not temperature-dependent.
It fluctuates randomly with temperature.
Why does the resistivity of a metal increase with temperature?
The number of free electrons decreases.
The positive ions in the lattice vibrate more, increasing collisions.
The applied voltage increases with temperature.
The current flow stops at higher temperatures.
What does the electromotive force (emf) of a battery represent?
The resistance within the battery.
The current supplied by the battery.
The energy provided per coulomb per charge.
The voltage drop across the battery terminals.
What causes the terminal voltage of a battery to be less than its emf?
External resistance.
Internal resistance.
Insufficient charge flow.
Overcharging the battery.
How does the internal resistance of a battery affect its performance?
It increases the available voltage for the circuit.
It reduced the available voltage.
It increases the energy output of the battery.
It has no effect on the circuit.
What is true about the total resistance in a parallel circuit?
It is greater than the largest individual resistance.
It is less than the smallest individual resistance.
It is equal to the sum of all individual resistances.
It depends only on the total current.
Kirchhoff's first rule (junction rule) is based on which law of physics?
Conservation of energy.
Conservation of charge.
Conservation of momentum.
Conservation of mass.
What does Kirchhoff's second rule state?
The total resistance in a circuit is zero.
The sum of currents entering a junction equals the sum leaving it.
The sum of potential differences in a closed loop is zero.
The total voltage in a circuit is infinite.
Why does the total resistance increase when resistors are connected in series?
Current divides across the resistors.
Voltage across each resistor decreases.
The current must pass through each resistor, adding their resistances.
The effective resistance depends only on the largest resistor.
Why is P = V2/R often used to calculate power loss in high-voltage transmission lines?
It emphasises the role of resistance in reducing power loss.
It shows that power loss is inversely proportional to the square of voltage.
It is independent of current, making it easier to calculate.
It demonstrates that power loss is independent of voltage.
What is the principle of a potential divider?
It divides current equally between two or more resistors.
It splits the voltage proportionally across resistors based on their resistances.
It ensures the same voltage is applied to all resistors.
It maintains constant current in the circuit.
Why is a potentiometer considered more accurate than a voltmeter for measuring emf?
It does not draw current from the circuit.
It has a higher internal resistance.
It measures current directly.
It requires no external power source.
What happens when the sliding contact of a potentiometer is moved closer to the voltage source?
The output voltage decreases.
The output voltage increases.
The resistance of the circuit increases.
The emf of the source decreases.
Which of the following is NOT a valid application of Kirchhoff's Laws?
Determining current distribution in a circuit.
Calculating voltage drops in loops.
Estimating the emf a battery.
Determining the mass of a circuit element.
