Current electricity practice · Mixed difficulty

Two wires have resistances $R\,\,\mathrm{and}\,\,2R$. When both are joining in series and in parallel, then ratio of heats generated in these situations on applying the same voltage, is

Statement-1: If a wire is stretched to increase its length $n$ times then its resistance also become $n$ time.
Statement-2: Resistance of the wire is directly proportional to its length.

Assertion: As a direct current passes through a thick metallic conductor, it produces magnetic field only outside the rod.
Reason: Current passes only along the surface of the conductor and not through the interior.

Ohm's law is applicable to :

The kirchhoff's first law $\left( {\sum i = 0} \right)$ and second law $\left( {\sum {\mkern 1mu} {\mkern 1mu} iR = 0} \right)$ where the symbols have their usual meanings, are respectively based on

The relation between Faraday’s constant $F$, electron charge $e$ and avogadro number $N$ is

The charge given to any conductor resides on its outer surface because

An electric heater kept in vacuum is heated continuously by passing electric current. Its temperature

What determines the emf between the two metals placed in an electrolyte?

$A,\,\,B,\,C$ and $D$ are four resistances of $2\,\,\mathrm{\Omega },\,\,2\,\,\mathrm{\Omega },\,\,2\,\,\mathrm{\Omega }\,\,\mathrm{and}\,\,3\,\,\mathrm{\Omega }$ respectively. They are used to form a Wheatstone bridge. The resistance $D$ is short circuted with a resistances $\mathrm{R}$ in order to get the bridge balanced. The value of $R$ will be

For a metallic wire, the ratio of voltage to corresponding current is

The emf of a battery A is balanced by a length of 80 cm on a potentiometer wire. The emf of a standard cell 1 V is balanced by 50 cm. The emf of A is

The resistivity of a wire depends on its

If ${R_1}\,\,\mathrm{and}\,\,{R_2}$ be the resistances of the filaments of $\mathrm{200}\,\,\mathrm{W}$ and $\mathrm{100}\,\,\mathrm{W}$ electric bulbs operation at $\mathrm{220}\,\,\mathrm{V}$, then $\left( {\frac{{{R_1}}}{{{R_2}}}} \right)$ is

If $\mathrm{2}\,\,\mathrm{A}$ of current is passed through $\mathrm{C}\,\mathrm{u}\,\mathrm{S}\,{\mathrm{O}_4}$ solution for $\mathrm{32}\,\,\mathrm{s}$, then the number of copper ions deposited at the cathode will be

A conducting wire of cross-sectional area $1 \mathrm{~cm}^2$ has $3 \times 10^{23} \mathrm{~m}^{-3}$ charge carriers. If wire carries a current of $24 \mathrm{~mA}$, the drift speed of the carrier is

On increasing the temperature of a conductor, its resistance increases because the

Twelve cells, each having emf E volt are connected in series and are kept in a closed box. Some of these cells are wrongly connected with positive and negative terminals reversed. This 12 cell battery is connected in series with an ammeter, an external resistance $\mathrm{R}$ ohm and a two-cell battery (two cells of the same type used earlier, connected perfectly in series). The current in the circuit when the 12-cell battery and 2-cell battery aid each other is $3 \mathrm{~A}$ and is $2 \mathrm{~A}$ when they oppose each other. Then the number of cell is 12-cell battery that are connected wrongly is:

A small drop of water falls from rest through a large height $h$ in air, the final velocity is proportional to:-

A dry cell of emf $\mathrm{1}\mathrm{.5 }\,\,\mathrm{V}$ and internal resistance $\mathrm{0}\mathrm{.10}\,\,\mathrm{\Omega }$ is connected across a resistor in series with a very low resistance ammeter. When the circuit is switched on, the ammeter reading settles to a steady rate of $\mathrm{2}\,\mathrm{A}$. Find $\left( \mathrm{i} \right)$ chemical energy consumption of the cell $\left( \mathrm{ii} \right)$ energy dissipation inside the cell $\left( \mathrm{iii} \right)$ energy dissipation inside the resistor $\left( \mathrm{iv} \right)$power output of source is

A piece of silver has a resistance of $1 ~\Omega$. What will be the resistance of a constantan wire of one-third length and one-half diameter, if the specific resistance of constantan is 30 times that of silver?

A steady current flows in a metal wire of non-uniform cross-section. Which quantity remains constant along the length of the wire?

A uniform wire of resistance $R$ is uniformly compressed along its length, until its radius becomes $n$ times the original radius. Now resistance of the wire becomes

The number of dry cells, each of e.m.f. $1.5\,\,volt$ and internal resistance $0.5\,\,ohm$ that must be joined in series with a resistance of $20\,\,ohm$ so as to send a current of $0.6\,\,ampere$ through the circuit is

A copper wire is stretched to make it 0.5% longer. The percentage change in its electrical resistance, if its volume remains unchanged is

A resistor develops 500 J of thermal energy in 20 S, when a current of 1.5A is passed through it. If the current is increased from 1.5A to 3A, what will be the energy developed in 20S?

Kirchhoff's first law $\left(\sum {i}=0\right)$ expresses the conservation of

Thermoelectric constant of a thermocouple are $\alpha$ and $\beta .$. Thermoelectric power at inversion temperature is

Two bulbs rates $(25 {~W}-200 {~V})$ and $(100 {~W}-$ $220 {~V}$ ) are connected in series to a $440 {~V}$ line. Which one is likely to fuse?

Which one of the following is the resistance that must be placed parallel with $12 \Omega$ resistance to obtain a combined resistance of $4 \Omega$ ?