Physics Current Electricity

The resistance of platinum wire at $0^{?}\mathrm{C}$ is $2\mathrm{\Omega }$ and $6.8\mathrm{\Omega }$ at ${80}^{?}\mathrm{C}$ . The temperature coefficient of resistance of the wire is:

Three resistors having resistances r₁,r₂ and r₃ are connected as shown in the given circuit. The ratio i₂/i₃ of currents in terms of resistances used in the circuit is:

The effective resistance of a parallel connection that consists of four wires of equal length, equal area of cross-section and same material is 0.25Ω. What will be the effective resistance if they are connected in series?

Resistance of a carbon resistor determined from colour codes is $(22000\pm 5\mathrm{\%})\mathrm{\Omega }$ . The colour of third band must be:

Where can I get the Current Electricity Class 12 important questions?

Column -I gives certain physical terms associated with flow of current through a metallic conductor. Column - II gives some mathematical relations involving electrical quantities. Match Column - I and Column - II with appropriate relations.

In a potentiometer circuit a cell of EMF $1.5\mathrm{V}$ gives balance point at $36\mathrm{c}\mathrm{m}$  length of wire. If another cel) of EMF 2.5 V replaces the first cell, then at what length of the wire, the balance point occurs?

A ball is projected with a velocity, $10{\mathrm{m}\mathrm{s}}^{-1}$ , at an angle of ${60}^{?}$  with the vertical direction, its speed at the highest pint of its trajectory will be :

10 resistors, each of resistance $\mathrm{R}$ are connected in series to a battery of emf $\mathrm{E}$ and negligible internal resistance. Then those are connected in parallel to the samebattery, the current is increased $\mathrm{n}$ times. The value of $n$  is:

The resistance of platinum wire at $0^{\circ }\mathrm{C}$ is $2\mathrm{\Omega }$ and $6.8\mathrm{\Omega }$ at ${80}^{\circ }\mathrm{C}$ . The temperature coefficient of resistance of the wire is: