- Question 1
The correct answer is: (D)
The null point is found at 40 cm from the left end when resistance X is balanced against another resistance Y. If the resistance X is shunted by a resistance 4X, the null point will be shifted by 10 cm.
- Question 2
The correct answer is: (C)
The balancing length AJ = 300 cm. When the jockey is moved from A to C, the balancing length decreases by 60 cm.
Therefore, R = 300 × 60/240 = 36 Ω.
- Question 3
The correct answer is: (A)
In the Wheatstone bridge, the resistances P and Q are interchanged. The change in the bridge balance will be no change.
The reason is that the bridge balance depends on the ratio of resistances P/Q and R/S. When P and Q are interchanged, the ratio P/Q remains the same. Therefore, the bridge balance will not change.
