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4. Electricity and magnetism
A section of Physics, 0625
Listing 10 of 2294 questions
A circuit contains two fixed resistors and a light‑dependent resistor (LDR). shows that the power supply is a 9.0 V battery. 450 Ω 800 Ω 9.0 V The current in the 450 Ω resistor is 0.012 A. State what is meant by electric current. The current in the LDR is I1 and the current in the 800 Ω resistor is I2. Complete the equation that relates the current in the 450 Ω resistor to I1 and I2. current in the 450 Ω resistor = Calculate the power dissipated in the 800 Ω resistor. power = The brightness of the light that is incident on the LDR increases. Explain what happens to the potential difference (p.d.) across the 450 Ω resistor.
0625_w21_qp_41
THEORY
2021
Paper 4, Variant 1
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shows current–potential difference (p.d.) graphs for a resistor, a thermistor and a filament lamp. p.d. / V 0.2 0.4 0.6 current / A 0.8 1.0 filament lamp filament lamp resistor resistor thermistor thermistor The resistor, the thermistor and the filament lamp are connected in series with a power supply. Draw a circuit diagram for this circuit. Add a voltmeter to your circuit diagram in in a correct position to measure the p.d. across the resistor. Using the graph in , determine the p.d. across the terminals of the power supply when the p.d. across the resistor is 6.0 V. p.d. across terminals of power supply = Describe a practical use for a thermistor.
0625_w21_qp_43
THEORY
2021
Paper 4, Variant 3
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and each show an electrical circuit. Each circuit has two lamps connected to an electrical supply. X Y circuit circuit State the term used to describe each electrical circuit. Write the term under each circuit. State two disadvantages of the circuit in . 1. 2. Redraw the circuit in with switches that will turn lamps X and Y on and off independently of each other. shows another circuit. K W Z J S1 S2 The lamps can be turned on and off using two different switches S1 and S2. Complete the table stating when the lamps are on or off. The first one has been done for you. switch positions lamps on or off S1 S2 K Z off K W J W J Z
0625_m19_qp_32
THEORY
2019
Paper 3, Variant 2
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shows an electric kettle. The power input of the kettle is 1.5 kW. The potential difference of the mains electrical supply for the kettle is 220 V. Calculate the current in the kettle when it is switched on. current in kettle = A The 1.5 kW kettle is used for a total of 4.0 hours. The cost of 1.0 kW h of electrical energy is 14 pennies . Calculate the cost of the energy used by the kettle in 4.0 hours. cost of energy = p shows an overloaded extension lead. Explain the danger of connecting too many plugs to an extension lead.
0625_m23_qp_32
THEORY
2023
Paper 3, Variant 2
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Questions Discovered
2294