Question 1 - Case Based Questions (MCQ) - Chapter 12 Class 10 - Electricity

Observe the graph and answer any four questions from (a) to (e). V-I graph for a conductor is as shown in figure.

Question 1 (a)

(a) What do you infer from this graph?

(i) V ∝ 1/I

(ii) V ∝ I ²

(iii) V ∝ I

(iv) V ∝ 1/I ²

Answer:

The V-I graph is a straight line graph passing through the origin.

This implies that V is directly proportional to I.

So, the correct answer is (iii ).

Question 1 (b)

Name the physical quantity represented by the slope of this graph 

(i) Current

(ii) Resistance

(iii) Potential difference

(iv) None of the above

Answer:

The slope of the V-I graph gives the resistance.

So, the correct answer is (ii).

Question 1 (c)

Ohm is the SI unit of:

(i) Potential difference

(ii) Resistance

(iii) Current

(iv) Resistivity

Answer:

The SI unit of resistance is ohm .

So, the correct answer is (ii).

Question 1 (d)

Which of the following law justify the above graph: 

(i) Faradays Law

(ii) Ohm’s Law

(iii) Faradays Law

(iv) Joule’s Law

Answer:

Ohm’s law , states that the current passing through a conductor is directly proportional to the potential difference across its ends, provided the physical conditions like temperature, density etc. remain unchanged.

The V-I graph given above also states that current is directly proportional to potential difference.

So, the correct answer is (ii).

Question 1 (e)

Resistance of a conductor depends on: 

(i) length of conductor

(ii) area of cross-section

(iii) temperature

(iv) all of the above

Answer:

Factors affecting resistance of a conductor are:

• Length of the conductor
• Area of cross section
• Nature of Material
• Temperature

Since all the factors are mentioned in the options.

So, the correct answer is (iv).