A student measures the terminal potential difference $(V)$ of a cell (of emf $\varepsilon$ and internal resistance $r$) as a function of the current $(I)$ flowing through it. The slope and intercept of the graph between $V$ and $I,$ then respectively, equal:
1. $\varepsilon$ and $-r$
2. $-r$ and $\varepsilon$
3.   $r$ and $-\varepsilon$
4. $-\varepsilon$ and $r$

A current of 3A flows through the 2$\Omega$ resistor shown in the circuit. The power dissipated in the $5\Omega$ resistor is

1. 4 W                                             
2. 2 W
3. 1 W                                             
4. 5 W

A wire of a certain material is stretched slowly by ten per cent. Its new resistance and specific resistance become respectively 1. .

An electric kettle takes 4 A current at 220 V. How much time will it take to boil 1 kg of water from temperature ${20}^{°}$C? The temperature of boiling water is ${100}^{°}$C

1. 6.3 min

2. 8.4 min

3. 12.6 min

4. 4.2 min

A cell can be balanced against 110cm and 100 cm of potentiometer wire, respectively with and without being short-circuited through a resistance of $10 \Omega$. Its internal resistance is 

1. 1.0 $\Omega$

2. 0.5 $\Omega$

3. 2.0 $\Omega$

4. zero 

In the circuit shown, the current through the $4~\Omega$ resistor is $1~\text{A}$ when the points $P$ and $M$ are connected to a DC voltage source. The potential difference  between the points $M$ and $N$ is: 

1. $1.5~\text{V}$
2. $1.0~\text{V}$
3. $0.5~\text{V}$
4. $3.2~\text{V}$

In the figure a long uniform potentiometer wire AB is having a constant potential gradient along its length. The null points for the two primary cells of emfs E₁ and E₂ connected in the manner shown are obtained at a distance of 120 cm and 300 cm from the end A. Find (i) $\frac{E_1}{E_2}$and  position of null point for the cell E₁.

How is the sensitivity of a potentiometer increased ?

Using Kirchoffs rules determine the value of unknown resistance R in the circuit so that no current flows through 4 Ω resistance. Also find the potential difference between A and D.

A capacitor of capacitance 5 μF is connected as shown in the figure. The internal resistance of the cell is 0.5 Ω. The amount of charge on the capacitor plate is?

1. 0 μC

2. 5 μC

3. 10 μC

4. 25 μC

In the circuit here, the steady state voltage across capacitor C is a fraction of the battery e.m.f. The fraction is decided by 

1. R₁ only

2. R₁ and R₂ only

3. R₁ and R₃ only

4. R₁, R₂ and R₃