List of top Physics Questions on Cells, Emf, Internal Resistance

A low voltage supply from which one needs high currents must have very low internal resistance. Why ?

A battery of emf 21 V and internal resistance 3 \(\Omega\) is connected to a resistor. If the current in the circuit is 3 A, find:
(i) the resistance of the resistor, and
(ii) the terminal voltage of the battery.

Two cells of emf \(E_1\) and \(E_2\) with internal resistances \(r_1\) and \(r_2\) respectively, are connected in parallel by connecting their positive terminals together and negative terminals together. Deduce an expression for equivalent emf and equivalent internal resistance of the combination.

A parallel combination, as stated in (a) above, of two cells of emfs \(E\) and \(3E\) and internal resistances \(R\) each is connected across a resistance \(2R\). Find the current that flows through resistance \(2R\).

An electric iron rated \(2.2\,\text{kW},\,220\,\text{V}\) is operated at \(110\,\text{V}\) supply. Find: (i) its resistance, and (ii) heat produced by it in \(10\) minutes.

Two cells of emf \(E_1\) and \(E_2\) with internal resistances \(r_1\) and \(r_2\) respectively, are connected in parallel by connecting their positive terminals together and negative terminals together. Deduce an expression for equivalent emf and equivalent internal resistance of the combination.

A parallel combination, as stated in (a) above, of two cells of emfs \(E\) and \(3E\) and internal resistances \(R\) each is connected across a resistance \(2R\). Find the current that flows through resistance \(2R\).

An electric iron rated \(2.2\,\text{kW},\,220\,\text{V}\) is operated at \(110\,\text{V}\) supply. Find: (i) its resistance, and (ii) heat produced by it in \(10\) minutes.

Five cells, each of emf \((E)\) and internal resistance \((r)\), are connected in series. If out of these five cells, one of the cells is connected with opposite polarity, the equivalent emf and internal resistance of the combination, respectively, will be

For a cell or a battery, the emf is (A) equal to the potential difference between its terminals when terminals are not connected externally (B) less than the potential difference between its terminals when the cell/battery is being discharged (C) always greater than the potential difference between its terminals (D) less than the potential difference between its terminals when the cell/battery is being charged Choose the correct answer from the options given below:

A battery of emf \(15\ \text{V}\) and internal resistance of \(4\ \Omega\) is connected to a resistor. If the current in the circuit is \(2\ \text{A}\), the resistance of the resistor and terminal voltage of the battery will be:

The value of current \(I\) in the electrical circuit as given below, when potential at \(A\) is equal to the potential at \(B\), will be _____ A. graphics[width=0.5\linewidth]{Q5.png}

In the circuit shown below, the potential difference between A and B is: graphics[width=0.5\linewidth]{Q1.png}

A battery of emf 12 V and internal resistance 3 \(\Omega\) is connected to an external resistor. If the current in the circuit is 0.6 A, the voltage across the external resistor will be

In the circuit shown in the figure, the input voltage V_i is 20V, V_BE = 0 and V_CE = 0. The values of I_B , I_C and β are given by

The internal resistance of a 2.1 V cell which gives a current of 0.2 A through a resistance of 10 Ω is

The resistances of the four arms P, Q, R and S in a Wheatstone's bridge are 10 ohm, 30 ohm, 30 ohm and 90 ohm, respectively. The e.m.f. and internal resistance of the cell are 7 volt and 5 ohm respectively. If the galvanometer resistance is 50 ohm, the current drawn from the cell will be