An electric motor runs on a dc source of emf E and internal resistance r. Show that the power output of the source, is maximum when the current drawn by the motor is `(E)/(2r)`.

Find the current drawn from a cell of emf 1V and internal resistance 2/3 Omega connected to the network given adjoint.

n cells of e.m.f E and internal resistance r are connected in series with an external resistance R . the current will increase n times that of a single cell, if

When does a source of current deliver maximum power?

n cells, each having emf. E and internal resistance r are connected in parallel. What is the net internal resistance of the combination?

A storage battery of a car has an e.m.f. of 12V. If the internal resistance of the battery is 0.4 Omega , what is the maximum current that can be drawn from the battery?

The storage battery of a car has an emf of 12 V. If the internal resistance of the battery is 0.4Omega , what is the maximum current that can be drawn from the battery?

First a set of n equal resistors of R each are connected in series to a battery of emf E and internal resistance R. A current I is observed to flow. Then, the n resistors are connected in parallel to the same battery. It is observed that the current is increased 10 times. What is 'n'?