IB Physics- B.5-Qc#15- A lighting system consists of two long metal rods

Topic 5 and topic 11 transformers.
A lighting system consists of two long metal rods with a potential difference
maintained between them. Identical lamps can be connected between the rods as required.
The following data are available for the lamps when at their working temperature.
Lamp specifications 24 V, 5.0 W
Power supply emf 24 V
Power supply maximum current 8.0 A
Length of each rod 12.5 m
Resistivity of rod metal 7.2 × 10 Ω m
Each rod is to have a resistance no greater than 0.10 Ω. Calculate, in m,
the minimum radius of each rod. Give your answer to an appropriate
number of significant figures.
c. One advantage of this system is that if one lamp fails then the other
lamps in the circuit remain lit. Outline one other electrical advantage of
this system compared to one in which the lamps are connected in series.
HL:
A step-down transformer is used to transfer energy to the two rods. The primary coil of this transformer is connected to an alternating mains supply that has an emf of root mean square (rms) magnitude 240 V. The transformer is 95 % efficient.
Outline how eddy currents reduce transformer efficiency.
e. Determine the peak current in the primary coil when operating with
the maximum number of lamps.
topic 5 electricity playlist:

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Note: the induction lesson can be found in theme D4