Physics MCQs for NEET — Practice Questions with Answers

The context states: 'Kirchhoff’s junction rule is based on conservation of charge and the outgoing currents add up and are equal to incoming current at a junction.' This directly links the junction rule to the conservation of charge.

The context states: 'Loop rule: The algebraic sum of changes in potential around any closed loop involving resistors and cells in the loop is zero (Fig. 3.15).' This is a direct statement of the loop rule.

The context states: 'If ultimately I is determined to be positive, the actual current in the resistor is in the direction of the arrow. If I turns out to be negative, the current actually flows in a direction opposite to the arrow.'

The context mentions: '$V = V(P) – V(N) = e – I r$ [Eq. (3.38) between the positive terminal P and the negative terminal N; I here is the current flowing from N to P through the cell].'

The context explains: 'The proof of this rule follows from the fact that when currents are steady, there is no accumulation of charges at any junction or at any point in a line. Thus, the total current flowing in, (which is the rate at which charge flows into the junction), must equal the total current flowing out.'

The context states: 'The formulae we have derived earlier for series and parallel combinations of resistors are not always sufficient to determine all the currents and potential differences in the circuit. Two rules, called Kirchhoff’s rules, are very useful for analysis of electric circuits.'

The context states: 'Junction rule: At any junction, the sum of the currents entering the junction is equal to the sum of currents leaving the junction (Fig. 3.15). For example, Fig. 3.15 shows I3 = I1 + I2, where I3 enters and I1, I2 leave.

The context states: 'If, while labelling the current I through the cell one goes from P to N, then of course $V = e + I r$ (3.60).'

The context mentions: 'Given a circuit, we start by labelling currents in each resistor by a symbol, say I, and a directed arrow to indicate that a current I flows along the resistor in the direction indicated.'

The context states: 'Gustav Robert Kirchhoff (1824 – 1887) German physicist... Mainly known for his development of spectroscopy, he also made many important contributions to mathematical physics, among them, his first and second rules for circuits.'