Physics Current Electricity

In the given circuit, r = 2 W. The power dissipated in the circuit is ______W.

If the current through an incandescent lamp decreases by 20%, how much change will be there in its illumination?

The length of a potentiometer wire is ?. A cell of emf E is balanced at a length ?/4 from the positive end of the wire. If the length of the wire is increased by ?/2, at what distance will the same cell give a balanced point? (Potentiometer battery is ideal)

The area of cross-section of cylindrical wire increases uniformly from left to right as shown in figure. When steady current flows in the wire, then in the direction of current

In the circuit shown in figure, what is the value of I0 just after pressing the key K?

In a meter bridge experiment, the galvanometer shows a null point when jockey is pressed at 40.0 cm using a standard resistance of 100 W as per the diagram. The least count of the scale used is 1 mm. The unknown resistance is nearly

Resistance of given carbon resistor is

A uniform wire of resistance $R$ is stretched uniformly to $n$ times. It is then cut to form five wires of equal length. These wires are arranged as shown in figure. the effective resistance between $A$ and $C$ is

What is a galvanometer according to current and electricity class 12 Physics chapter?

How many types of electricity in current electricity for class 12?