Would you prefer a vlotmeter or a potentiomer to measure the emf of a battery?

The length of a wire of a potentiometer is 100 cm, and the e.m.f. of its standard cell is E volt. It is employed to measure the e.m.f. of a battery whose internal resistance is 0.5 Omega . If the balance point is obtained at I = 30 cm from the positive end, the e.m.f. of the battery is . where i is the current in the potentiometer wire.

In an experiment to measure emf epsilon_(1) of a battery by a potentionmeter , the main circuit uses a battery of emf epsilon_(2) . Then.

n resistors each of resistance r are connected to a battery of emf epsilon and internal resistance r. Then the ratio of terminal voltage to emf of battery = ...... .

A battery of emf 2.0 V and internal resistance 0.10 Omega is being charged with a current of 5.0 A . Find the potential difference between the terminals of the battery?

A battery of emf 2.0 V and internal resistance 0.10 Omega is being charged with a current of 5.0 A . Find the potential difference between the terminals of the battery?

A potentiometer wire of length L and a resistance r are connected in series with a battery of e.m.f. E_(0) and a resistance r_(1) . An unknown e.m.f E is balaned at a length l of the potentiometer wire. The e.m.f E will be given by :

Silver and copper voltmeters are connected in parallel with a battery of emf 12V . In 30 minutes, 1g of silver and 1.8g of copper are liberated. The power supplied by the battery is (Z_(Cu) = 6.6xx10^(-4) g//C and Z_(Ag) = 11.2xx10^(-4)g//C )

When a voltameter is connected across a battery which is connected with external resistance 280 Omega to measure its emf, it reads 1.4 V. Now when this emf is measured by potentiometer, it is measured as 1.55 V. Now if maximum power is to be spent in the external resistance then its value should be made equal to ...... .