Current Electricity - Electricity - Physics Previous Year Questions

An unknown resistance X is to be determined using resistances R\(_1\), R\(_2\) or R\(_3\). Their corresponding null points are A, B and C. Find which of the above will give the most accurate reading and why ?

In the given diagram, a line of force of a particular force field is shown. Out of the following options, it can never represent

Consider a cylindrical element as shown in the figure. The current that flows through the element is I and resistivity of material of the cylinder is $\rho$. Choose the correct option out the following

A resistance of 2 \(\Omega\) is connected across one gap of a metre-bridge (the length of the wire is 100 cm) and an unknown resistance, greater than 2 \(\Omega\), is connected across the other gap. When these resistance are interchanged, the balance point shifts by 20 cm. Neglecting any corrections, the unknown resistance is

STATEMENT - 1

In a Meter Bridge experiment, null point for an unknown resistance is measured. Now, the unknown resistance is put inside an enclosure maintained at a higher temperature. The null point can be obtained at the same point as before by decreasing the value of the standard resistance.

and

STATEMENT - 2

Resistance of a metal increases with increase in temperature.

Figure shows three resistor configurations R1, R2 and R3 connected to 3 V battery. If the power dissipated by the configuration R1, R2 and R3 is P1, P2 and P3, respectively, then

For the circuit shown in the figure

When two identical batteries of internal resistance 1 \(\Omega\) each are connected in series across a resistor R, the rate of heat produced in R is J₁. When the same batteries are connected in parallel across R, the rate is J₂. If J₁ = 2.25 J₂, then the value of R in \(\Omega\) is __________.

Incandescent bulbs are designed by keeping in mind that the resistance of their filament increases with the increase in temperature. If at room temperature, 100, 60 and 40 W bulbs have filament resistances R₁₀₀, R₆₀ and R₄₀ respectively, the relation between these resistances is

To verify Ohm's law, a student is provided with a test resitor R_T, a high resistance R₁, a small resistance R₂, two identical galvanometers G₁ and G₂, and a variable voltage source V. The correct circuit to carry out the experiment is

Consider a thin square sheet of side L and thickness, made of a material of resistivity \(\rho\). The resistance between two opposite faces, shown by the shaded areas in the figure is

A meter bridge is set up as shown, to determine an unknown resistance X using a standard 10 \(\Omega\) resistor. The galvanometer shows null point when tapping-key is at 52 cm mark. The end-corrections are 1 cm and 2 cm, respectively, for the ends A and B. The determined value of X is

Two batteries of different emfs and different internal resistance are connected as shown. The voltage across AB in volts is __________.

For the resistance network shown in the figure, choose the correct option(s).

If the direct transmission method with a cable of resistance 0.4 \(\Omega\) km^\(-\)1 is used, the power dissipation (in %) during transmission is

During an experiment with a metre bridge, the galvanometer shall a null point when the jockey is pressed at 40.0 cm using a standard resistance of 90\(\Omega\), as shown in the figure. The least count of the scale used in the meter bridge is 1 mm. The unknown resistance is