9. Electricity
A section of Physics, 9702
Listing 10 of 370 questions
Electric current is a flow of charge carriers. The charge on the carriers is quantised. Explain what is meant by quantised. A battery of electromotive force (e.m.f.) 9.0 V and internal resistance 0.25 Ω is connected in series with two identical resistors X and a resistor Y, as shown in . X 0.15 1 0.15 1 2.7 1 Y X 0.251 9.0 V battery The resistance of each resistor X is 0.15 Ω and the resistance of resistor Y is 2.7 Ω. Show that the current in the circuit is 2.8 A. Calculate the potential difference across the battery. potential difference = V Each resistor X connected in the circuit in is made from a wire with a cross-sectional area of 2.5 mm2. The number of free electrons per unit volume in the wire is 8.5 × 1029 m–3. Calculate the average drift speed of the electrons in X. drift speed = m s–1 The two resistors X are replaced by two resistors Z made of the same material and length but with half the diameter. Describe and explain the difference between the average drift speed in Z and that in X.
9702_s16_qp_22
THEORY
2016
Paper 2, Variant 2
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Questions Discovered
370