Using a potentiometer, balance points are obtained at 60 cm and 10 cm with two cells connected in series first to support one another and then in opposition respectively. Find the ratio of the emfs of the cells.

With a certain cell, the balance point is obtained at 65 cm from the end of apotentiometer wire. With another cell whose emf differs from that of the first by 0.1V the balance point is obtained at 60cm. Find the emf of each cell.

In a potentiometer arrangement, a cell of emf 1.25 V gives a balance point at 35.0 cm length of the wire. If the cell is replaced by another cell and the balance point shifts to 63.0 cm, what is the emf of the second cell?

You are given a potentiometer, a rheostat, one key, a driving cell for potentiometer, one galvanometer, two cells of unknown e.m.f., one two way key and some connecting wires. Using all those given drawa circuitdiagram for finding j the ratio ofthe e.m.fofthe two cells.

A cell can be balanced against 110 cm and 100 cm of potentiometer wire respectively when in open circuit and when short circuited through a resistance of 10 Omega . Find the internal resistance of the cell.

There are two poles on each on either bank of a river just opposite to each other.One pole is 60m high.From the top of this pole the angles of depression of the top and the foot of the other pole are 30° and 60° respectively. Find the width of the river and the height of the other pole.

An aeroplane when flying at a height of 3125mfrom the ground passes vertically below another plane at an instant when the angles of elevation of the two planes from the same point on the ground are 30° and 60° respectively. Find the distance between the two planes at the instant.

A potentiometer wire of length 100 cm has a resistance of 10 ohm. It is connected in series with a resistance and a battery of emf 2V and of negligible internal resistance. A source of emf 10mV is balanced against a length of 40 cm of the potentiometer wire. What is the value of the external resistance?

Two poles of equal heights are standing opposite each other on either side of the road,which is 80m wide.From a point between them on the road,the angles of elevation of the top of the poles are 60^@ and 30^@ respectively.Find the height of the poles and the distances of the point from the poles.