Electricity - 1 - Free MCQ Practice Test with solutions, UPSC Sci & Tech

In an electric circuit all other elements are connected in series but a voltmeter is connected in parallel.

it's  one of the three primary factors (length, cross-sectional area, and nature of material) directly used in calculating resistance using the formula R = ρL/A.

In parallel combination, the equivalent resistance is smaller than the least resistance used in the circuit.

In a parallel circuit, the voltage across each device connected between points A and B remains the same because:

• All devices share the same potential difference.

Therefore, the correct answer is voltage.

Electrical resistance depends on how easily electrons can move through a material. In conductors like pure metals, when temperature increases, the atoms of the metal vibrate more. These increased vibrations cause more collisions with moving electrons, which increases resistance.

Alloys are made by mixing two or more metals or a metal with a non-metal (for example, nichrome is an alloy of nickel and chromium). In alloys, the atoms are already irregularly arranged. This irregular structure creates obstruction to the flow of electrons even at normal temperature.

Alloys have a very low temperature coefficient of resistance. When the temperature of an alloy is increased, the increase in atomic vibrations does not significantly increase the obstruction to electron flow. As a result, the change in resistance is very small.

Hence, the resistance of an alloy is considered nearly constant with rise in temperature.

So, Correct Option: A

Three resistors of 2Ω is required to get 6Ω because resultant is more than individual so they all must be connected in parallel.

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.

Resistance = slope line of V-I graph

In the circuit shown, the resistors B, C and D are connected in series.

The key points regarding resistors in series are:

• Resistors are said to be in series when they are connected end to end.
• The total resistance in a series circuit is the sum of the individual resistances.
• In this case, the resistors B, C, and D form a single path for the current to flow.
• The current remains the same through all resistors in series.

Thus, the resistors B, C, and D are the ones connected in series in this network.