Current electricity practice · Mixed difficulty

Each side of regular polygon of $n$ sides has a resistance $R.$ The equivalent resistance between any two adjacent vertices is

Two bulbs are working in parallel order. Bulb $A$ is brighter than bulb $B$. If ${R_A}$ and ${R_B}$ are their resistance respectively then

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, $I=n e A v_{{d}}$.

An ammeter and a voltmeter of resistance $R$ are connected in series to an electric cell of negligible internal resistance. Their readings are $A$ and $V$ respectively. If another resistance $R$ is connected in parallel with the voltmeter

An electric current passes through a circuit containing two wires of the same material connected in parallel. If the lengths of the wires are in the ratio of $\mathrm{4/3}$ and radius of the wires are in the ratio of $\mathrm{2/3}$, then the ratio of the current passing through the wires will be

When current is passed in antimony-bismuth couple, then

To deposit one gm equivalent of an element at an electrode, the quantity of electricity needed is

Kirchhoff’s first law $i.e.\,\,\sum i = 0$ at a junction is based on the law of conservation of

A battery of $\mathrm{24}\,\,\mathrm{cells}$, each of emf $1.5\,\,V$ and internal resistance $2\,\,\mathrm{\Omega }$ is to be connected in order to send the maximum current through a $12\,\,\mathrm{\Omega }$ resistor. The correct arrangement of cells will be

A resistor $R$ has power of dissipation $P$ with cell voltage $E$. The resistor is cut in $n$ equal parts and all parts are connected in parallel with same cell. The new power dissipation is

A current of $10 \mathrm{~amp}$ is passing through a metallic wire of cross sectional area $4 \times 10^{-6} \mathrm{~m}^2$. If the density of the aluminum conductor is $2.7 \,\mathrm{gm/cc}$ considering aluminum gives 1 electrons per atom for conduction find the drift speed of the electrons if molecular weight of aluminum is $27 \mathrm{~gm}$.

Kirchoff’s second law for the analysis of circuit is based on

A wire has a resistance of $\mathrm{3}\,\,\mathrm{\Omega }$. It is cut into two parts and both half values are connected in parallel. The new resistance is

On passing the current in water voltmeter, hydrogen

A wire $\mathrm{X}$ is half the diameter and half the length of a wire $\mathrm{Y}$ of similar material. The ratio of resistance of $X$ to that of $Y$ is

Four wires $AB,\,\,BC,\,\,CD,\,\,DA$ of resistance $4\,\,ohm$ each and a fifth wire $BD$ of resistance $8\,\,ohm$ are joined to form a rectangle $A\,B\,C\,D$ of which $BD$ is a diagonal. The effective resistance between the points $A$ and $B$ is

A uniform wire of length $l$ and radius $r$ has a resistance of $100\,\Omega$ . It is recast into a wire of radius $\frac{r}{2}$. The resistance of new wire will be

An AC generator of $220\,\,V$ having internal resistance $r = 10\,\,\mathrm{\Omega }$ and external resistance $R = 100\,\,\mathrm{\Omega }$. What is the power developed in the external circuit

Which statement is true?
(i) Kirchoff’s law is equally applicable to both $\mathrm{AC}$ and $\mathrm{DC}$.

(ii) Semiconductors have a positive temperature coefficient of resistance.

(iii) Meter bridge is greater sensitive when the resistance of all four arms of the bridge is of the same order.

(iv) The emf of a cell depends upon the size and area of electrodes.

Choose the incorrect statement out of the following

The chemical equivalent of silver is $\mathrm{108}$. If the current in a silver voltmeter is $2\,\,amp$, the time required to deposit $27\,\,grams$ of silver will be

The length of the wire is doubled. Its conductance will be

Assertion: The drift velocity of electrons in a metallic wire will decrease, if the temperature of the wire is increased.

Reason: On increasing temperature, conductivity of metallic wire decreases.

To draw maximum current from a combination of cells, how should the cells be grouped?

To measure the internal resistance of a battery, potentiometer is used. For $\mathrm{R}=10 \Omega$, the balance point is observed at $\ell=500 \mathrm{~cm}$ and for $\mathrm{R}=1 \Omega$ the balance point is observed at $\ell=400 \mathrm{~cm}$. The internal resistance of the battery is approximately:

Two cells when connected in series are balanced on 8 m on a potentiometer. If the cells are connected with polarities of one of the cells reversed, they balance on 2 m. The ratio of e.m.f.'s of the two cells is

Drift velocity ${v_d}$ varies with the intensity of electric field as per the relation

The reciprocal of resistance is

The temperature of cold junction of thermocouple is $0\,^\circ C$. If the neutral temperature is $270\,^\circ C$, then the inversion temperature is

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