A torch bulb rated as 4.5 W, 1.5 V is connected as shown in the figure. The emf of the cell needed to make the bulb glow at full intensity is

In meter bridge, the balancing length from left end when standard resistance of 1 Ω is in right gap is found to be 20 cm. The value of unknown resistance is

A Daniel cell is balanced on 125 cm length of a potentiometer wire. When the cell is short circuited with a 2 Ω resistance, the balancing length obtained is 100 cm. Internal resistance of the cell will be

A network of resistors is connected to a 16 V battery with internal resistance of 1Ω. Compute the equivalent resistance of the network.

A resistance of R Ω draws current from a potentiometer. The potentiometer has a total resistance R₀ Ω as shown in the Fig below. A voltage V is supplied to the potentiometer. Derive an expression for the voltage across R when the sliding contact is in the middle of the potentiometer.

In a meter bridge as shown, the balance point is found to be at 39.5 cm from the end A, when the resistor Y is of 12.5 Ω. Determine the balance point of the bridge above if X and Y are interchanged.

The figure below shows a potentiometer with a cell of 2.0 V and internal resistance 0.40 Ω maintaining a potential drop across the resistor wire AB. A standard cell which maintains a constant emf of 1.04 V (for very moderate currents up to a few mA) gives a balance point at 67.3 cm length of the wire. To ensure very low currents drawn from the standard cell, a very high resistance of 600 kΩ is put in series with it, which is shorted close to the balance point. The standard cell is then replaced by a cell of unknown emf ε and the balance point, found similarly, turns out to be at 82.3 cm length of the wire. What is the value ε?

The figure below shows a 2.0 V potentiometer used for the determination of internal resistance of a 1.5 V cell. The balance point of the cell in open circuit is 76.3 cm. When a resistor of 9.5 Ω is used in the external circuit of the cell, the balance point shifts to 64.8 cm length of the potentiometer wire. Determine the internal resistance of the cell.

Equal potentials are applied on an iron and copper wire of same length. In order to have same current flow in the wire, the ratio (r_iron/r_copper) of their radii must be

The V-i graph for a conductor at temperature T1 and T2 are as shown in the figure. (T2 - T1) is proportional to

Length of a hollow tube is 5 m, its outer diameter is 10 cm and thickness of its wall is 5 mm. If resistivity of the material of the tube is 1.7 x 10^{-8} Ω m, then the resistance of the tube will be

Five resistances are combined according to the figure. The equivalent resistances between the points X and Y will be

A wire of resistance 0.5 Ωm^-1 is bent into a circle of radius 1m. The same wire is connected across a diameter AB as shown in the fig. The equivalent resistance is

A metal rod of length 10 cm and a rectangular cross-section of 1cm x ½ cm is connected to a battery across opposite faces. The resistance will be:

Kirchhoff’s II law for the electric network is based on:

Determine the electric current through branch BD of the electric network:

WSB experiment is most sensitive, when:

In a Whetstone’s bridge, all the four arms have equal resistance R. If resistance of the galvanometer arm is also R, then equivalent resistance of the combination is:

For a cell of e.m.f. 2 V, a balance is obtained for 50 cm of the potentiometer wire. If the cell is shunted by a 2 ohm resistor and the balance is obtained across 40 cm of the wire, then the internal resistance of the cell is:

For a cell, the terminal potential difference is 3.6 V, when the circuit is open. If the potential difference reduces to 3 V, when cell is connected to a resistance of 5 Ω, the internal resistance of cell is:

The temperature coefficient of resistance for a wire is 0.00125 /°C. At 27°K its resistance is 1 ohm. The temperature at which the resistance becomes 2 ohm is:

Drift velocity v_d varies with the intensity of electric field as per the relation:

A cell of internal resistance 3 ohm and emf 10 volt is connected to a uniform wire of length 500 cm and resistance 3 ohm. The potential gradient in the wire is:

In a Whetstone’s bridge, all the four arms have equal resistance R. If resistance of the galvanometer arm is also R, then equivalent resistance of the combination is

Across a wire of length l and thickness d, a P.D of V is applied. If the p.d. is doubled then the drift velocity becomes-

Which is the dimensional formula for resistance from the given below?

Two electric bulbs whose resistances are in the ratio of 1:2 are connected in parallel to a constant voltage source the power dissipated in them have the ratio-

The resistance of a copper coil is 4.64Ω at 40°C and 5.6Ω at 100°C. Its resistance at 0°C will be:

A uniform wire is cut into 10 segments increasing in length in equal steps. The resistance of shortest segment is R and the resistance of the other segments increases in steps of 6Ω. If the resistance of the longest segment is 3R, then the value of R is:

One ideal cell is used to drive current in a metre bridge circuit. In an experiment x is the balancing length obtained. If we replace the wire of the metre bridge with another wire of material having more resistivity and lesser diameter, the new balancing length will be:

If the coil of a heater is cut to reduce its length by 20% then effect on its power will be:

There are N emf E and internal resistance r connected in series with each other. But n cells are connected with reverse polarity and n < N/2. Effective emf and internal resistance of this combination are:

Two bulbs A and B of 200 W and 50 W, respectively are designed for the same voltage. The material and total length of the filament wire used in both the cases are same. The ratio of radius of cross section of filament of bulb A to that of the bulb B is:

EMF of a cell depends:

There is a definite potential difference between the two ends of a potentiometer. Two cells are connected in such a way that the first time they support each other, and the second time they oppose each other. They are balanced on the potentiometer wire over a 100 cm and 50 cm length respectively. Then E1/E2 will be:

A 12 cm wire is given shape of a of a right angled triangle PQR having sides PQ = 3 cm, QR = 4 cm and RP = 5 cm. The resistance between two ends (PQ, QR, RP) of the respective sides are measured one by one by a multimeter. The resistances will be in the ratio

EMF is most closely related to:

An energy source will supply a constant current into the load if its internal resistance is:

What is the effect on the product of resistivity and conductivity of a conductor when its temperature is increased?

The number of free electrons per 10 mm of an ordinary copper wire is about 2 × 10²¹. The average drift speed of the electrons is 0.25 mm/s. The current flowing is:

When no current flows through a conductor:

The length of a potentiometer wire is L. A cell of emf E is balanced at length L/3 from the positive end of the wire. If the length of the wire is increased by L/2. At what distance will the same cell give a balanced point:

Specific resistance of a conductor increases with :-

The voltage V and current I graph for a conductor at two different temperatures T₁ and T₂ are shown in the figure. The relation between T₁ and T₂ is

In the following circuit a 10 m long potentiometer wire with resistance 1.2 ohm/m, a resistance R₁ and an accumulator of emf 2 V are connected in series. When the emf of thermocouple is 2.4 mV then the deflection in galvanometer is zero. The current supplied by the accumulator will be

The current in a conductor varies with time t as $$I = 2t + 3t^2$$ where I is in ampere and t in seconds. Electric charge flowing through a section of the conductor during t = 2 sec to t = 3 sec is

The effective resistance between points P and Q of the electrical circuit shown in the figure is

The resistance of a wire is 10^{-6} \Omega per metre. It is bend in the form of a circle of diameter 2 m. A wire of the same material is connected across its diameter. The total resistance across its diameter AB will be

A 10 m long wire of 20Ω resistance is connected with a battery of 3 volt e.m.f. (negligible internal resistance) and a 10 Ω resistance is joined to it in series. Potential gradient along wire in volt per meter is

A galvanometer has 30 divisions and a sensitivity 16 μA/div. It can be converted into a voltmeter to read 3 V by connecting

The resistance of an ideal ammeter is

We have a galvanometer of resistance 25 Ω. It is shunted by a 2.5 Ω wire. The part of total current that flows through the galvanometer is given as

For comparing the e.m.f.'s of two cells with a potentiometer, a standard cell is used to develop a potential gradient along the wires. Which of the following possibilities would make the experiment unsuccessful?

If in the experiment of Wheatstone's bridge, the positions of cells and galvanometer are interchanged, then balance points will

An energy source will supply a constant current into the load if its internal resistance is

Current provided by a battery is maximum when

Two batteries of e.m.f. 4V and 8V with internal resistances 1Ω and 2Ω are connected in a circuit with a resistance of 9Ω. The current and potential difference between the points P and Q are:

Consider the circuit given here with the following parameters: E.M.F. of the cell = 12V. Internal resistance of the cell = 2Ω. Resistance R = 4Ω Which one of the following statements is true?

Kirchhoff's first and second laws for electrical circuits are consequences of:

AB is a wire of potentiometer with the increase in the value of resistance R, the shift in the balance point J will be

In a current carrying conductor, the ratio of the electric field and the current density at a point is called

When a metal conductor connected to left gap of a meter bridge is heated, the balancing point

In parallel combination of n cells, we obtain

A cell having an emf E and internal resistance r is connected across a variable external resistance R. As the resistance R is increased, the plot of potential difference V across R is given by

In the series combination of two or more than two resistances

An electric heater is connected to the voltage supply. After few seconds, current gets its steady value then its initial current will be

If a certain piece of copper is to be shaped into a conductor of minimum resistance, its length (L) and cross-sectional area (a) shall respectively be

Copper wire is used as connecting wire because :

The specific resistance of a conductor increases with :

In an experiment with potentiometer, null point with a cell is found at 240 cm. When the cell is shunted with a resistance 2 Ω, the null point becomes 120 cm internal resistance of cell is :

An electric heating element consumes 500 W, when connected to a 100 V line. If the line voltage becomes 150 V, the power consumed Will be:

Potentiometer measures the potential difference more accurately than a voltmeter because:

The SI unit of mobility is

The resistance of a tungsten filament at 150°C is 133 ohm. What will be its resistance at 500°C? The temperature coefficient of resistance is tungsten is 0.0045 per °C.

The drift velocity of free electrons in a conducting wire carrying a current is v. If the wire of same material but double of its radius the current is now 2i, then the drift velocity of electrons will be:

The electric current in electrolytes is due to the flow of

A 10 V battery of negligible internal resistance is charged by 120V d.c. supply. If the resistance in the circuit is 22 ohm, the value of charging current is:

Which of the following statement is correct for Kirchhoff’s laws?

The maximum power drawn out of the cell (with emf E and internal resistance r) from a source is given by:

The variation of potential difference V with length l in case of two potentiometers A and B is shown in graph below. Choose the correct statement.

Which of the following statements are not correct for non-ohmic resistors?

Which of the following instrument is simplest practical application of Wheatstone bridge?

In an experiment of meter bridge, a null point is obtained at the Centre of the bridge wire. When a resistance of 20 ohm is connected in one gap, the value of resistance in other gap is

Drift velocity is equal to

The length of a conductor is doubled and its radius is halved, its resistance is

The example of a non ohmic resistance is

Specific resistance of all metals is mostly effected by

In the given fig the value of current I is

To get a maximum current through a resistance of 2.5Ω, one can use m rows of cells each row having n cells. The internal resistance of each cell is 0.5 Ω. What are the values of m and n if the total no of cell is 20?

In the circuit if the galvanometer deflection is zero what is the value of x

In a circuit with two resistors R₁ and R₂ connected in series, if R₁ = 3Ω and R₂ = 6Ω, what is the total resistance of the circuit?

A 60 W bulb and a 100 W bulb are connected in parallel to a 230 V supply. What is the total power consumed by the bulbs?

When a 12 V battery is connected across a resistor of 4 Ω, what is the current flowing through the resistor?

In a circuit with three resistors of values 4 Ω, 6 Ω, and 12 Ω connected in series, what is the total resistance?

A 100 W bulb and a 60 W bulb are connected in series to a 240 V supply. What is the voltage across the 100 W bulb?

When two resistors of 5 Ω and 15 Ω are connected in parallel, what is the equivalent resistance?