Current electricity practice · Medium

The time rate of flow of charge through any cross-section of a conductor is _____

The electromotive force of a primary cell is $2\,\,volt$. When it is short-circuited it gives a current of $4\,\,ampere$. Its internal resistance in $ohm$ is

Statement-1: When an insulated wire is bent, its resistivity increases.
Statement-2: On bending, the velocity of electron decreases.

A thermocouple is formed by two metals $X$ and $Y$, metal $X$ comes earlier to $Y$ in Seebeck series. If temperature of hot junction increases beyond the temperature of inversion, then direction of current in thermocouple will be from

Find the correct answer.

For electroplating a spoon, it is placed in the voltmeter at

A thermocouple of resistance $1.6\,\,\mathrm{\Omega }$ is connected in series with a galvanometer of $8\,\,\mathrm{\Omega }$ resistance. The thermocouple develops an $e.$.m.f. of $10\,\,\mu V$ per degree temperature difference between two junctions. When one junction is kept at $0\,{\,^0}\mathrm{C}$ and the other in a molten metal, the galvanometer reads $8\,\,millivolt$. The temperature of molten metal, when $e$.m.f. varies linearly with temperature difference, will be

The chemical equivalent of copper and zinc are $\mathrm{32 }\,\mathrm{and }\,\mathrm{108}$ respectively. When copper and silver voltmeters are connected in series and electric current is passed through for sometime, $1.6\,\,g$ of copper is deposited. Then, the mass of silver deposited will be

The thermo emf of a thermo-couple is found to depend on temperature $T$ (in degree Celsius) as $E = 4\,T - \frac{{{T^2}}}{{200}}$, where $T\,{\,^0}\mathrm{C}$ is the temperature of the hot junction. The neutral and inversion temperature of the thermocouple are (in degree celsius)

The equivalent resistance of two resistors connected in series is $6 \Omega$ and their parallel equivalent resistance is $\frac{4}{3} \Omega$. What are the values of resistances?

Though the electron drift velocity is small and electron charge is very small, a conductor can carry an appreciably large current because:

Statement-I: KVA is the unit of electrical power and kWh is the unit of electrical energy.
Statement-II: Both kVA and kWh have same dimensions

Assertion (A): When electric bulbs of different
powers but of same rated voltage are connected in
series, the lower power bulb glows more bright.

Reason (R): In an electric bulb most of the electrical
energy is wasted as heat energy.

The specific resistance of wire

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

Pick out the wrong feature about carbon resistors

For a given temperature difference which of the following pairs will generate maximum thermo-emf?

In a large building, there are 15 bulbs of 40 W, 5 bulbs of 100 W, 5 fans of 80 W and 1 heater of 1 kW. The voltage of the electric mains is 220 V. The minimum capacity of the main fuse of the building will be

The amount of charge flowing per second per unit area normal to the flow is called

A conductor wire having ${10^{29}}$ free $\mathrm{electrons}\,\,/\,\,{\mathrm{m}^3}$ carries a current of $\mathrm{20}\,\mathrm{A}$. If the cross-section of the wire is $1\,\,\mathrm{m}{\mathrm{m}^2}$, then the drift velocity of electrons will be

24 identical electrical cells, internal resistance of each $0.5 \Omega$ are used in mixed combination to obtain maximum current through external resistance of $3 \Omega$. Calculate number of rows and number of cells in each row.

In a metre bridge the balancing point is found to be at $39.5 \mathrm{~cm}$ from $\mathrm{A}$, when the resistor $\mathrm{Y}=12.5 \Omega$. The value of $\mathrm{X}$ is

In voltaic air cell if $\mathrm{5}\,\,\mathrm{g}$ zinc is consumed, how many ampere hours shall we get?

The tolerance of a carbon resistor with colour code Brown Black Red

A cylindrical metal wire of length $l$ and cross sectional area $S$, has resistance $R$, conductance $G$, conductivity σ and resistivity $\rho$. Which one of the following expressions for $\sigma$ is valid

Two electric bulbs have ratings respectively of $\mathrm{25}\,\,\mathrm{W, 220}\,\,\mathrm{V}$ and $\mathrm{100}\,\,\mathrm{W, 220}\,\,\mathrm{V}$. If the bulbs are connected in series with a supply of $\mathrm{440}$, which bulb will fuse?

A steady current of $1 \mathrm{~A}$ is flowing through the conductor. The number of electrons flowing through the cross-section of the conductor in $1 \mathrm{~sec}$ is:

Identify the set in which all the three materials are good conductors of electricity:

When current is passed in antimony-bismuth couple, then

Assertion (A) : Two non-ideal batteries are connected in parallel with same polarities on same side. The equivalent emf is smaller than either of the two emfs.

Reason (R) : Two non-ideal batteries are connected in parallel, the equivalent internal resistance is smaller than either of the two internal resistances.