4.3. Electric circuits
A subsection of Physics, 0625, through 4. Electricity and magnetism
Listing 10 of 426 questions
shows a circuit that contains a battery, a switch, a voltmeter and three 40 Ω resistors, R1, R2 and R3. V R1 R3 R2 The switch is open and resistors R1 and R2 form a potential divider. Describe what is meant by a potential divider. The reading on the voltmeter is 7.5 V. Calculate the electromotive force (e.m.f.) of the battery. e.m.f. = The switch is closed. Calculate the resistance of the complete circuit. resistance = Calculate the reading on the voltmeter when the switch is closed. reading =
0625_s23_qp_41
THEORY
2023
Paper 4, Variant 1
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10 The circuit in shows an electromagnetic relay being used to switch an electric motor on and off. The relay coil has a much greater resistance than the potential divider. M switch 6 V motor power supply for motor contacts relay core pivoted iron armature The relay operates when there is a potential difference of 3 V across the coil. On , mark the position of the slider of the potential divider when the relay just operates. Describe how the relay closes the contacts in the motor circuit.
0625_w08_qp_2
THEORY
2008
Paper 2, Variant 0
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Questions Discovered
426