While connecting 6 cells in a battery in series,ina tape recorder,by mistake one cell is connected with reverse polarity.If the effective resistance of load is 24 ohm and internal resistance of each cell is one ohm and emf 1.5V,the current delivered by the battery is

A potentiometer having a 4m long wire is connected to the terminals of a battery of constant output voltage. A Leclanche cell has a balancing length of 1m. If the length of the potentiometer wire is increased by 1m, then the position of the null point is

Two wires of the same material but of different diameters carry the same current I. If the ratio of their diameters is 2 : 1, then the corresponding ratio of their mean drift velocities will be

In a thermo couple the temperature of the cold junction is 15⁰C.If the temperature of inversion is 485⁰C,the neutral temperature of the thermo couple is

The resistance of a conductor is 1.08Ω.To reduce it to 1Ω,the resistance that must be connected is

If π is Peltier coefficient,heat evolved at a junction when a current of 10 mA passes for 10 seconds in joules is

A galvanometer of resistance 20Ω is to be shunted so that only 1% of the current passes through it.shunt connected is

A cell of emf e₁ in the secondary circuit gives null deflection for1.5m length of potentiometer of wire length 10m.If another cell of emf e₂ is connected in series with e₁ then null reflection was obtained for 2.5 m length.Then e₁:e₂

When two unknown resistances are placed in the gaps of meterbridge,the null point is found to be 40cm from one end of the bridge wire.when one of the resistances is shunted with a 10 ohm coil,the null points is 25cm form the same end.The value of each of the unknown resistances is

In a potentiometer experiment, when a resistance of 10 ohm is connected in parallel to the cell in secondary circuit , the balancing length is 350 cm. when 10 ohm resistance is replaced by 20 ohm resistance, the balancing length becomes 420 cm.The internal resistance of the cell in secondary circuit is