Electric Current Through Conductors Physics - Electric Current Through Conductors

Five dry cells each of voltage 1.5 V are connected as shown in diagram

What is the overall voltage with this arrangement?

100 cells each of emf 5 V and internal resistance 1 Ω are to be arranged so as to produce maximum current in a 25 Ω resistance. Each row contains equal number of cells. The number of rows should be

The internal resistance of a cell of emf 2 V is 0.1 Ω, it is connected to a resistance of 0.9 Ω. The voltage across the cell will be

Masses of three pieces of wires made of the same metal are in the ratio 1 : 3 : 5 and their lengths are in the ratio 5 : 3 : 1. The ratios of their resistances are

The wire of length L and resistance R is stretched so that its radius of cross-section is halved. What is its new resistance?

State the basic categories of electrical cells.

State SI unit of resistivity.

Define one ohm.

An electric current in a metallic conductor such as a wire is due to flow of electrons, the negatively charged particles in the wire. What is the role of the valence electrons which are the outermost electrons of an atom?

State advantages and disadvantages of cells in parallel.

State advantages of cells in series.

What is a real e.m.f. device?

A current of 4 A flows through an automobile headlight. How many electrons flow through the headlight in a time of 2 hrs?

Find the colour code for the following value of resistor having tolerance ± 10%.
i. 330 Ω
ii. 100 Ω
iii. 47 kΩ
iv. 160 Ω
v. 1 kΩ

Find the value of resistances for the following colour code.
i. Blue Green Red Gold
ii. Brown Black Red Silver
iii. Red Red Orange Gold
iv. Orange White Red Gold
v. Yellow Violet Brown Silver

Prove that the current density of a metallic conductor is directly proportional to the drift speed of electrons.

DC current flows in a metal piece of non uniform cross-section. Which of these quantities remains constant along the conductor: current, current density or drift speed?