List of top Electrical and Electronics Measurements Questions on Measurement of voltage asked in GATE IN

In which of the following bridge(s) is the balancing condition frequency-independent?
The figure shows a Chromel-Alumel thermocouple, where the junction A is held at temperature \( T_A \), and a thermal emf \( E_1 \) is measured using an ideal voltmeter between the open ends B1 and B2, both held at temperature \( T_B \). Two identical copper wires are introduced between B1-C1 and B2-C2 as shown in the figure. When C1 and C2 are held at temperature \( T_C \), the voltmeter reads a thermal emf \( E_2 \). Then, _________
The resistance of a pure copper wire of length 10 cm and diameter 1 mm is to be measured. The most suitable method from amongst the choices given below is _________.