Question

Can anyone help me with these questions? TIA!!

Answer 1

Hey There!

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Question 1:

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`\Huge\text{Resistance:}`

Resistance is a material's tendency to resist the flow of charge (current). Resistance is the measure of the opposition to motion of free electrons(current) due to their continuous collisions with the atom of the lattice. An electric current flows when electrons move through a conductor, such as a metal wire. The moving electrons can collide with the atoms in the metal. This makes it more difficult for the current to flow, and causes resistance. The unit of Resistance is "OHM". Ohm is denoted by the greek letter "Ω".

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Question 2:

`\Huge\text{Ohm's Law}`

If a current 'I' is caused to flow in a conductor by a battery of potential difference 'V', it is found that the current is directly proportional to potential difference provided there is no change in the conductor itself. That means more will be I if we increase V. So

`{\Longrightarrow}\qquad \qquad \qquad I {\propto} V\\\\{\Longrightarrow}\qquad \qquad \qquad I = KV`

Where K is Conductance. Conductance is the ability of a conductor to allow the current to pass through it. Resistance(R) is the reciprocal(opposite) of conductance(K) thus K is inversely proportional to R,

`{\Longrightarrow}\qquad \qquad \qquad I = (1)/(R)V \\\\{\Longrightarrow}\qquad \qquad \qquad V = IR`

This is known as OHM's Law, and V = IR is the equation linking the R, V and I.

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Question 3:

`\Huge\text{Circuit Diagram:}`

Circuit Diagram no 1 attached is of this question. In the circuit diagram, V is voltmeter to find the potential difference, A is the ammeter to find the current, R is the resistance i.e. the conductor wire, The switch and the battery.

Suppose the wire of length 100 cm is connected to a battery, the Voltmeter observes the potential difference and ammeter reads the current of the wire. We will use the R, V and I i.e. V = IR equation to find out the resistance of that wire and Record the resistance. Then attach another small wire of suppose 90 cm to the battery, and similarly Find out its resistance too. After recording the resistance 3 or 4 times, you will observe that When you decrease the length of the wire,

• The Resistance decreases
• The Current increases
• The Potential Difference decreases

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Question 4:

`\Huge\text{Resistance:}`

The resistance of a conductor depends upon the following factors.

• Length(L), Longer the length of conductor, Greater the resistance.

`{\Longrightarrow}\qquad \qquad \qquad R\quad {\propto}\quad L`

• Cross-Sectional Area(A), thicker the Wire, lesser the Resistance.

`{\Longrightarrow}\qquad \qquad \qquad R\quad {\propto}\quad (1)/(A)`

• Material of the Conductor, The Resistance also changes because of the material of the wire. If we use copper it will have different resistance than the steel wire.

The relation between only length of the wire and resistance is
`R\quad {\propto} \quad L` . The relation of R, L and A is given by, ρ

`{\Longrightarrow}\qquad \qquad \qquad R\quad {\propto}\quad (L)/(A)\\\\{\Longrightarrow}\qquad \qquad \qquad R\quad =\ \frac{\ {\rho}\ L\ }{A}`

Where ρ is known as resistivity depends upon the nature of the material of the wire. The meter of resistivity is Ω x m(Ohm x meter).

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Question 5:

`\Huge\text{I-V Characteristic:}`

I-V curves of an electrical device or component, are a set of graphical curves which are used to define its operation within an electrical circuit. I-V characteristic curves show the relationship between the current flowing through an electronic device and the applied voltage across its terminals. The circuit diagram to find I-V characteristic must have a resistor which is a device or component connected to a battery which is providing the potential difference V. When a resistor is connected to a battery, current I is observed due to drift velocity. To find the current and potential difference(voltage) the circuit must have the Ammeter and voltmeter. Recorded current and voltage must be used to plot the graph to check the I-V characteristic. The picture attached is the circuit diagram.

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Question 6:

We calculate the resistance at constant temperature by ohm's law. The Ohms law is applied at constant temperature because the resistance of any material varies with the change in temperature. It shows a linear relationship between the applied voltage and the resulting current, resistance being a constant. So we could use V = IR because resistance is constant at constant temperature.

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Best Regards,

'Borz'