Current Electricity

Consider a fuse wire of length $l$ and radius $r$ ．The time of heating $(t)$ for passing the maximum current will depend on

Consider a circuit where a cell of emf \(E_0\) and internal resistance \(\mathrm{r}\) is connected across the terminal \(\mathrm{A}\) and \(\mathrm{B}\) as shown in figure. The value of \(\mathrm{R}\) for which the power generated in the c...

An amount of charge Q passes through a coil of resistance R. If the current in the coil decreases to zero at a uniform rate during time T, then the amount of heat generated in the coil will be,

In an experiment on a circuit as shown in the figure, the voltmeter shows 8 V reading. The resistance of the voltmeter is,

A battery of emf E and internal resistance r is connected with an external resistance R as shown in the figure. The battery will act as a constant voltage source if

Two metal wires of identical dimensions are connected in series. If \(\sigma\)1 and \(\sigma\)2 are the electrical conductivities of the metal wires respectively, the effective conductivity of the combination is

The carbon resistor with colour code is shown in the figure. There is no fourth band in the resistor. The value of the resistance is

Consider the circuit shown.If all the cells have negligible internal resistance, what will be the current through the 2\(\Omega\)
resistor when steady state is reached?

What will be the equivalent resistance between the terminals A and B of the infinite resistive network shown in the figure?

A galvanometer can be converted to a voltmeter of full scale deflection V0 by connecting a series resistance R1 and can be converted to an ammeter of full scale deflection I0 by connecting a shunt resistance R2. What is the current flowing ...

Five identical capacitors, of capacitance 20\(\mu\)F each, are connected to a battery of 150V, in a combination as shown in the diagram. What is the total amount of charge stored?

When the value of R in the balanced Wheatstone bridge, shown in the figure, is increased from 5\(\Omega\) to 7\(\Omega\), the value of S has to be increased by 3\(\Omega\) in order to maintain the balance. What is the initial values of S...

In the circuit shown in the figure all the resistance are identical and each has the value r\(\Omega\). The equivalent resistance of the combination between the points A and B will remain unchanged even when the following pairs of points m...

What is the current I shown in the given circuit?

A capacitor of capacitance C is connected in series with a resistance R and DC source of emf E through a key. The capacitor starts charging when the key is closed. By the time the capacitor has been fully charged, what amount of energy is d...

What will be current through the 200\(\Omega\) resistor in the given circuit, a long time after the switch K is made on?

An electric bulb, a capacitor, a battery and a switch are all in series in a circuit. How does the intensity of light vary when the switch is turn on?

Four resistors, 100\(\Omega\), 200\(\Omega\), 300\(\Omega\) and 400\(\Omega\) are connected to form four sides of a square. The resistors can be connected in any order. What is the maximum possible equivalent resistance across the diago...

A non-zero current passes through the galvanometer G shown in the circuit when the key K is closed and its value does not change when the key is opened. Then, which of the following statement(s) is/are true?

Consider the circuit given here. The potential difference VBC between the points B and C is

Consider the circuit shown in the figure where all the resistances are of magnitude 1 k\(\Omega\). If the current in the extreme right resistance X is 1 mA, the potential difference between A and B is

Six wires, each of resistance r, are connected so as to form a tetrahedron. The equivalent resistance of the combination when current enters through one corner and leaves through some other corner is

Consider the circuit shown in the figure.The value of the resistance X for which the thermal power generated in it is practically independent of small variation of its resistance is

Two wires of same radius having lengths l1 and l2 and resistivities \({{\rho _1}}\) and \({{\rho _2}}\) are connected in series. The equivalent resistivity will be

Two equal resistances, 400 \(\Omega\) each, are connected in series with a 8 V battery. If the resistance of first one increases by 0.5%, the change required in the resistance of the second one in order to keep the potential difference acro...

The effective resistance between A and B in the figure is \({7 \over {12}}\Omega\) if each side of the cube has 1\(\Omega\) resistance. The effective resistance between the same two points, when the link AB is removed, is

A 60 W - 220 V bulb is connected in series with another bulb 40 W - 220 V. Which bulb will give more illuminance ?

Two wires each of same material and same length have 2 L 1 ratio of their radii. If the first wire has a resistance of 2 \(\Omega\) then what will be the equivalent resistance of the two wires when they are connected in series?

A thin wire of resistance 4 \(\Omega\) is bent to form a circle. The resistance across any diameter is

A battery of e.m.f. E and internal resistance r is connected to an external resistance R the condition for maximum power transfer is