Current Electricity
Physics ⇒ Electricity and Magnetism
Current Electricity starts at 8 and continues till grade 12.
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See sample questions for grade 12
Define electromotive force (emf).
Describe the difference between direct current (DC) and alternating current (AC).
Describe the effect of temperature on the resistance of a metallic conductor.
Explain the term 'internal resistance' of a cell.
Explain why metals are good conductors of electricity.
A battery of emf 9 V and internal resistance 0.5 Ω is connected to a load resistor of 4.5 Ω. Calculate the energy dissipated as heat in the internal resistance when 10 C of charge flows through the circuit.
A potentiometer wire of length 1 m has a resistance of 10 Ω. It is connected in series with a 490 Ω resistor and a 5 V battery. What is the potential gradient along the potentiometer wire?
A student connects a voltmeter across a resistor in a circuit and observes that the voltmeter reading is less than the actual potential difference across the resistor. What could be the reason for this observation?
The resistance of a wire depends on which of the following factors?
(1) Length of the wire
(2) Cross-sectional area
(3) Material of the wire
(4) All of the above
Which law states that the algebraic sum of currents entering a junction is zero?
(1) Ohm's Law
(2) Kirchhoff's Current Law
(3) Faraday's Law
(4) Lenz's Law
Which of the following devices is used to measure electric current?
(1) Voltmeter
(2) Ammeter
(3) Galvanometer
(4) Potentiometer
Which of the following is NOT a property of an ideal voltmeter?
(1) Infinite resistance
(2) Zero resistance
(3) Connected in parallel
(4) Measures potential difference
Fill in the blank: The direction of conventional current is from __________ to __________ potential.
Fill in the blank: The drift velocity of electrons is typically of the order of __________ m/s.
Fill in the blank: The reciprocal of resistance is called __________.
Fill in the blank: The SI unit of electric charge is __________.
True or False: In a series circuit, the current is the same through all components.
True or False: The drift velocity of electrons in a conductor is typically much less than the speed of light.
True or False: The power dissipated in a resistor is given by P = I2R.
True or False: The resistance of a semiconductor decreases as temperature increases.
