Current Electri...

For comparing the e.m.f.\'s of two cells with a potentiometer, a standard cell is used to develop a potential gradient along the wires. Which of the following possibilities would make the experiment unsuccessful?

A potentiometer wire of length L and resistance 10 Ω is connected in series with a battery of e.m.f. 2.5 V and a resistance in its primary circuit. The null point corresponding to a cell of e.m.f. 1 V is obtained at a distance L/2. If the resistance in the primary circuit is doubled then the position of new null point will be

An ammeter with internal resistance 90 Ω reads 1.85 A when connected in a circuit containing a battery and two resistors 700 Ω and 410 Ω in series. Actual current will be

The circuit shown here is used to compare the e.m.f.\'s of two cells E₁ and E₂ (E₁> E₂). The null point is at C when the galvanometer is connected to E₁. When the galvanometer is connected to E₂, the null point will be

In an experiment to measure the internal resistance of a cell by potentiometer, it is found that the balance point is at a length of 2m when the cell is shunted by a 5 Ω resistance; and is at a length of 3m when the cell is shunted by a 10 Ω resistance. The internal resistance of the cell is, then

A potentiometer circuit shown in the figure is set up to measure e.m.f. of a cell E. As the point P moves from X to V the galvanometer G shows deflection always in one direction, but the deflection decreases continuously until Y is reached. In order to obtain balance point between X and Y it is necessary to

In the Wheatstone\'s bridge (shown in figure) X = Y and A >B. The direction of the current between ab will be

In the Wheatstone bridge shown below, in order to balance the bridge, we must have

A resistance of 4 Ω and a wire of length 5 metres and resistance 5 Ω are joined in series and connected to a cell of e.m.f. 10 V and internal resistance 1 Ω. A parallel combination of two identical cells is balanced across 300 cm of the wire. The e.m.f. E of each cell is