Current electricity practice · Mixed difficulty

A capacitor of capacitance $C$ is charged by a battery of emf $E$ and internal resistance $r$. A resistance $2 r$ is also connected in series with the capacitor. The amount of heat liberated inside the battery by the time capacitor is $50 \%$ charged is

Ohm's law fails in which of the following cases

I. Potential $V$ depends on $I$ non-linearly.

II. The relation between ${V}$ and I depends on the sign of ${V}$ for the same absolute value of ${V}$.

III. $V$ depends on $I$ linearly.

Assertion: As temperature of a metallic current carrying the wire is increased, its resistance increases.
Reason: Decrease in temperature results in a decrease of electric field strength, along the conductor so that the current reduces.

Value of $I=\int\limits_{0}^1(2 x+1)^2 d x$ is

The heat developed in a system is proportional to the current though it

$40 \,{~W}, 220 \,{~V}$ and $110 \,{~W}, 220\, {~V}$ bulbs are connected in series with $440\, volt$ supply, then

The internal resistance of a cell is the resistance of :

Statement-1: If the radius of copper wire carrying a current is doubled, then the drift velocity of the electrons will become one fourth.
Statement-2: Drift velocity will change according to the relation, $I=n e A v_{{d}}$.

For a certain thermocouple the emf is $\begin{array}{llllllllllllllllllll} {E = aT + \,\,b{T^2}} \end{array}$, where $t\left( {\mathrm{in}\,{\,^0}\mathrm{C}} \right)$ is the temperature of hot junction, the cold junction is at $0\,{\,^0}\mathrm{C}$. The value of contants $a\,\,\mathrm{and}\,\,b$ are $10\,\, \times \,\,{10^{ - 6}}$ and $0.02\,\, \times \,\,{10^{ - 6}}$ respectively, then the temperature of inversion $\left( {\mathrm{in}\,{\,^0}\mathrm{C}} \right)$ will be

Choose the wrong statement regarding the experiment to identify a diode, an LED, a resistor and a capacitor

In a thermo-couple, one junction which is at $0\,^\circ C$ and the othe at $t{\mkern 1mu} {\mkern 1mu} ^\circ C$ the emf is given by $E = a{t^2} - b{t^2}$. The neutral temperature is given by

Statement-1: The equivalent resistance in series combination is larger than even the largest individual resistance.
Statement-2: The equivalent resistance of the parallel combination is smaller than even the smallest resistance.

A bulb of $\mathrm{220 V}$ and $\mathrm{300 W}$ is connected across $\mathrm{110 V}$ circuit, the percentage reduction in power is

Number of electrons flowing per second is a conductor carrying a current of $9 {~A}$ is_____

In which one of the following substances the resistance decreases with increase of temperature?

Statement-I: Net power supplied by a non-ideal battery is $\mathrm{Ei}-\mathrm{i}^2 \mathrm{r}$
Statement-II: Power consumed by internal resistance of a battery is $\mathrm{i}^2 \mathrm{r}$.

Which of the following material is the best conductor of electricity?

When two resistances ${R_1}\,\,\mathrm{and}\,\,{R_2}$ are connected in series, they consume $\mathrm{12}\,\,\mathrm{W}$ powers. When they are connected in parallel, they consume $\mathrm{50}\,\,\mathrm{W}$ powers. What the ratio of the powers of ${R_1}\,\,\mathrm{and}\,\,{R_2}$ ?

Two identical heater filaments are connected first in parallel and then in series. At the same applied voltage, the ratio of heat produced in same time for parallel to series will be:

As the temperature increases, the electrical resistance:

In a potentiometer experiment, the balancing length with a cell is $560\,cm$. When an external resistance of $10\,\Omega$ is connected in parallel to the cell the balancing length changes by $60\,cm$. The internal resistance of the cell in ohm is

In an experiment to measure the internal resistance of a cell by potentiometer, it is found that the balance point is at a length of $2\,\,m$ when the cell is shunted by a $5\,\,\mathrm{\Omega }$ resistance; and is at a length of $3\,\,m$ when the cell is shunted by a $10\,\,\mathrm{\Omega }$ resistance. The internal resistance of the cell is, then

Assertion (A)In a meter bridge experiment, null point for an unknown resistance is put inside an enclosure maintained at a higher temperature. The null point can be obtained at the same ${p}$ as before by decreasing the value of the standard resistance.

Reason (R) Resistance of metal increases with increase in temperature.

Two resistances are connected in two gaps of a meter bridge. The balance point is $\mathrm{20}\,\,\mathrm{cm}$ from the zero end. A resistance of $15\,\,\mathrm{\Omega }$ is connected is series with the smaller of the two. The null point shifts to $\mathrm{40}\,\,\mathrm{cm}$. The value of the smaller resistance in $\mathrm{ohm}$ is

When two resistances ${R_1}$ and ${R_2}$ are connected in series and parallel with $120\,\,V$ line power consumed will be $25\,\,W$ and $100\,\,W$ respectively. Then the ratio of power consumed by ${R_1}$ to that consumed by ${R_2}$ will be

Which of the following relation is wrong?

Lengths of two wires are $50 {~cm}, 100 {~cm}$ respectively and their diameters are $1 {~mm}, 2$ ${mm}$ then ratio between their specific resistances is

In a potentiometer experiment the balancing length, with a cell is $560\,cm$. When an external resistance of $10\,\Omega$ is connected in parallel to the cell, the balancing length changes by $60\,cm$. Find the internal resistance of the cell.

Statement-1: Current flows in a conductor only when there is an electric field within the conductor.
Statement-2: The drift velocity of electrons in the presence of electric field decreases.

A potential difference is applied across the ends of a metallic wire. If the potential difference is doubled, the drift velocity will