All elements of an electric circuit are connected in series except :
In an electric circuit all other elements are connected in series but a voltmeter is connected in parallel.
The least resistance obtained by using 2Ω , 4Ω, 1Ω and 100Ω is
In parallel combination, the equivalent resistance is Smaller than the least resistance used in the circuit.
A resistance wire is stretched so as to double its length. Its new resistivity will have a magnitude
When a wire is stretched, its resistivity remains unchanged. It is because resistivity of a conductor depends only on its material and is independent of its length or cross- section area.
Two devices are connected between two points say A and B in parallel. The physical quantity that will remain the same between the two points is
In parallel combination voltage remains same across two points.
The resistance of an alloy :
The resistance of an alloy increases with increase in temperature.
To get 2Ω resistance using only 6Ω resistors, the number of them required is
Three resistors of 2Ω is required to get 6Ω because resultant is more than individual so they all must be connected in parallel.
Three resistors of 1Ω, 2 Ω and 3 Ω are connected in series with a battery of 12 V as shown in figure. Values of potential differences V1, V2, V3 across the three resistors have respective values :
In series grouping current I is same throughout and potential differences are directly proportional to respective resistances.
In given circuit
∴ V1 = IR1 = 2 A x 1Ω = 2V,
V2 = IR2 = 2 A x 2 Ω = 4 V and
V3 = IR3 = 2 A x 3 Ω = 6 V.
The resistance whose V - I graph is given below is
Resistance = slope line of V-I graph
The diagram shows a network of four resistors which is connected to an electric source. Identify the resistors which are connected in series in this network :
In the circuit shown, the resistors B, C and D are connected in series.
A boy records that 4000 joule of work is required to transfer 10 coulomb of charge between two points of a resistor of 50Ω. The current passing through it is
Work done in transferring the charge