Current Electricity

The current I flowing through the given circuit will be __________A.

Two metallic wires of identical dimensions are connected in series. If \(\sigma_{1}\) and \(\sigma_{2}\) are the conductivities of the these wires respectively, the effective conductivity of the combination is :

A \(1 \mathrm{~m}\) long wire is broken into two unequal parts \(\mathrm{X}\) and \(\mathrm{Y}\). The \(\mathrm{X}\) part of the wire is streched into another wire W. Length of \(W\) is twice the length of \(X\) and the resistance of $$\mat...

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R.
Assertion A: Alloys such as constantan and manganin are used in making standard resistance coils.
Reason R: Constantan and manganin have v...

Current measured by the ammeter (A) in the reported circuit when no current flows through 10 \(\Omega\) resistance, will be ________________ A.

A meter bridge setup is shown in the figure. It is used to determine an unknown resistance R using a given resistor of 15 \(\Omega\). The galvanometer (G) shows null deflection when tapping key is at 43 cm mark from end A. If the end correc...

All resistances in figure are 1 \(\Omega\) each. The value of current 'I' is \({a \over 5}\) A. The value of a is _________.

Resistance of the wire is measured as 2 \(\Omega\) and 3 \(\Omega\) at 10\(^\circ\)C and 30\(^\circ\)C respectively. Temperature co-efficient of resistance of the material of the wire is :

As shown in the figure, a potentiometer wire of resistance \(20 \,\Omega\) and length \(300 \mathrm{~cm}\) is connected with resistance box (R.B.) and a standard cell of emf \(4 \mathrm{~V}\). For a resistance '\(R\)' of resistance box intr...

A wire of resistance R1 is drawn out so that its length is increased by twice of its original length. The ratio of new resistance to original resistance is :

An electrical bulb rated 220 V, 100 W, is connected in series with another bulb rated 220 V, 60 W. If the voltage across combination is 220 V, the power consumed by the 100 W bulb will be about _______ W.

Given below are two statements :
Statement I : A uniform wire of resistance \(80 \,\Omega\) is cut into four equal parts. These parts are now connected in parallel. The equivalent resistance of the combination will be \(5 \,\Omega\).
Statem...

The current density in a cylindrical wire of radius 4 mm is 4 \(\times\) 106 Am\(-\)2. The current through the outer portion of the wire between radial distances \({R \over 2}\) and R is ____________ \(\pi\) A.

A cell, shunted by a 8 \(\Omega\) resistance, is balanced across a potentiometer wire of length 3 m. The balancing length is 2 m when the cell is shunted by 4 \(\Omega\) resistance. The value of internal resistance of the cell will be _____...

A 72 \(\Omega\) galvanometer is shunted by a resistance of 8 \(\Omega\). The percentage of the total current which passes through the galvanometer is :

In the given circuit 'a' is an arbitrary constant. The value of m for which the equivalent circuit resistance is minimum, will be \(\sqrt {{x \over 2}}\). The value of x is __________.

The current density in a cylindrical wire of radius r = 4.0 mm is 1.0 \(\times\) 106 A/m2. The current through the outer portion of the wire between radial distances \({r \over 2}\) and r is x\(\pi\) A; where x is __________.

A \(1 \mathrm{~m}\) long copper wire carries a current of \(1 \mathrm{~A}\). If the cross section of the wire is \(2.0 \mathrm{~mm}^{2}\) and the resistivity of copper is \(1.7 \times 10^{-8}\, \Omega \mathrm{m}\), the force experienced by ...

In a meter bridge experiment, for measuring unknown resistance 'S', the null point is obtained at a distance \(30 \mathrm{~cm}\) from the left side as shown at point D. If R is \(5.6\) \(\mathrm{k} \Omega\), then the value of unknown resist...

Two sources of equal emfs are connected in series. This combination is connected to an external resistance R. The internal resistances of the two sources are \(r_{1}\) and \(r_{2}\) \(\left(r_{1}>r_{2}\right)\). If the potential difference ...

In the given figure of meter bridge experiment, the balancing length AC corresponding to null deflection of the galvanometer is \(40 \mathrm{~cm}\). The balancing length, if the radius of the wire \(\mathrm{AB}\) is doubled, will be _______...

(A) The drift velocity of electrons decreases with the increase in the temperature of conductor.
(B) The drift velocity is inversely proportional to the area of cross-section of given conductor.
(C) The drift velocity does not depend on the...

An aluminium wire is stretched to make its length, 0.4% larger. The percentage change in resistance is :

The equivalent resistance between points A and B in the given network is :

Resistances are connected in a meter bridge circuit as shown in the figure. The balancing length \(l_{1}\) is \(40 \mathrm{~cm}\). Now an unknown resistance \(x\) is connected in series with \(\mathrm{P}\) and new balancing length is found ...

The current I in the given circuit will be :

A potentiometer wire of length \(300 \mathrm{~cm}\) is connected in series with a resistance 780 \(\Omega\) and a standard cell of emf \(4 \mathrm{V}\). A constant current flows through potentiometer wire. The length of the null point for c...

A battery of \(6 \mathrm{~V}\) is connected to the circuit as shown below. The current I drawn from the battery is :

The total current supplied to the circuit as shown in figure by the 5 V battery is ____________ A.

A resistor develops 300 J of thermal energy in 15 s, when a current of 2 A is passed through it. If the current increases to 3 A, the energy developed in 10 s is ____________ J.

A teacher in his physics laboratory allotted an experiment to determine the resistance (G) of a galvanometer. Students took the observations for \({1 \over 3}\) deflection in the galvanometer. Which of the below is true for measuring value ...

The length of a given cylindrical wire is increased to double of its original length. The percentage increase in the resistance of the wire will be ____________ %.

If n represents the actual number of deflections in a converted galvanometer of resistance G and shunt resistance S. Then the total current I when its figure of merit is K will be:

Two cells of same emf but different internal resistances r1 and r2 are connected in series with a resistance R. The value of resistance R, for which the potential difference across second cell is zero, is :

Eight copper wire of length \(l\) and diameter \(d\) are joined in parallel to form a single composite conductor of resistance \(R\). If a single copper wire of length \(2 l\) have the same resistance \((R)\) then its diameter will be _____...

In the given figure, the value of Vo will be _____________ V.

Which of the following physical quantities have the same dimensions?

In a potentiometer arrangement, a cell of emf 1.20 V gives a balance point at 36 cm length of wire. This cell is now replaced by another cell of emf 1.80 V. The difference in balancing length of potentiometer wire in above conditions will b...

A current of 15 mA flows in the circuit as shown in figure. The value of potential difference between the points A and B will be:

In a potentiometer arrangement, a cell gives a balancing point at 75 cm length of wire. This cell is now replaced by another cell of unknown emf. If the ratio of the emf's of two cells respectively is 3 : 2, the difference in the balancing ...

Two identical cells each of emf 1.5 V are connected in parallel across a parallel combination of two resistors each of resistance 20 \(\Omega\). A voltmeter connected in the circuit measures 1.2 V. The internal resistance of each cell is :

A potentiometer wire of length 10 m and resistance 20 \(\Omega\) is connected in series with a 25 V battery and an external resistance 30 \(\Omega\). A cell of emf E in secondary circuit is balanced by 250 cm long potentiometer wire. The va...

What will be the most suitable combination of three resistors A = 2\(\Omega\), B = 4\(\Omega\), C = 6\(\Omega\) so that \(\left( {{{22} \over 3}} \right)\)\(\Omega\) is equivalent resistance of combination?

The voltage drop across 15\(\Omega\) resistance in the given figure will be ______________ V.

A square shaped wire with resistance of each side 3\(\Omega\) is bent to form a complete circle. The resistance between two diametrically opposite points of the circle in unit of \(\Omega\) will be ___________.

Consider a galvanometer shunted with 5\(\Omega\) resistance and 2% of current passes through it. What is the resistance of the given galvanometer ?

A resistor dissipates 192 J of energy in 1s when a current of 4A is passed through it. Now, when the current is doubled, the amount of thermal energy dissipated in 5s in _________ J.

The equivalent resistance of the given circuit between the terminals A and B is :

In the given figure, a battery of emf E is connected across a conductor PQ of length 'l' and different area of cross-sections having radii r1 and r2 (r2 < r1). Choose the correct option as one moves from P to Q :

For the circuit shown, the value of current at time t = 3.2 s will be _________ A.[Voltage distribution V(t) is shown by Fig. (1) and the circuit is shown in Fig. (2)]