Current Electricity MCQs (NEET, JEE Main) – Test 2

The potential difference (V_A – V_B) between the points A and B in the given figure is [NEET 2016]

A potentiometer wire is 100 cm long and a constant potential difference is maintained across it. Two cells are connected in series first to support one another and then in opposite direction. The balance points are obtained at 50 cm and 10 cm from the positive end of the wire in the two cases. The ratio of emf’s is [NEET 2016]

A potentiometer circuit has been set up for finding the internal resistance of a given cell. The main battery, used across the potentiometer wire, has an emf of 2.0 V and a negligible internal resistance. The potentiometer wire itself is 4 m long. When the resistance, R, connected across the given cell, has values of

(i) Infinity

(ii) 9.5 Ω,

the ‘balancing lengths’, on the potentiometer wire are found to be 3 m and 2.85 m, respectively.

The value of internal resistance of the cell is [AIPMT 2014]

Two large vertical and parallel metal plates having a separation of 1 cm are connected to a DC voltage source of potential difference X. A proton is released at rest midway between the two plates. It is found to move at 45° to the vertical JUST after release. Then X is nearly [IIT JEE 2012]

If a wire is stretched to make it 0.1% longer, its resistance will : [AIEEE 2011]