Kirchhoff's laws and applications
- A constant voltage of 50 V is maintained between the points A and B of the circuit shown in the figure. The current through the branch CD of the circuit is : Answer: 2. 2.0 A Key idea: C and D are joined by a wire, so they are at the same potential. The circuit becomes two parallel pairs in series... 1
- The current passing through the battery in the given circuit, is: Answer: 2. 0.5 A Key idea: the middle network is a balanced Wheatstone bridge, so the 6\ Ω resistor carries no current. Points C and D are j... 1
- The magnitude and direction of the current in the following circuit is Answer: 3. 0.5 A from A to B through E In the loop the two cells oppose each other (10 V and 5 V), so the net emf is 10-5=5 V. The 10 V cell... 1
- Three resistors having resistances r_1, r_2 and r_3 are connected as shown in the given circuit. The ratio i_3/i_1 of currents in terms of resistances used in the circuit is : Answer: 2. r₂/r₂+r₃ Key idea: r₂ and r₃ are in parallel, and the current i₁ splits in inverse ratio of resistances (current divider). i₃=i₁·... 1
- The potential difference (V_A-V_B) between the points A and B in the given figure is Answer: 3. +9 V Move from A to B and add the potential change across each element. Resistor 2 Ω in the direction of current: drop of 2×2=4 V... 1