A small tungsten filament lamp is supplied with increasing potential difference

PHYSICS · Multi-part · CBSE · Physics · Current Electricity · Current Electricity

Problem

A small tungsten filament lamp is supplied with increasing potential difference, and the following readings are obtained at room temperature: Voltage

V

(

\text{V}

2

4

6

8

10

Current

I

(

\text{A}

0.30

0.55

0.75

0.90

1.00

Use these data to answer the questions below. (i) Plot the graph of current

I

(vertical axis) versus potential difference

V

(horizontal axis). (ii) From your graph, find the average resistance of the lamp at

6\,\text{V}

. (iii) Draw a tangent to the curve at

V = 6\,\text{V}

and determine the dynamic (differential) resistance at this point. (iv) Using the value of current corresponding to

6\,\text{V}

, calculate the electrical power consumed by the filament at this voltage. (v) Does the filament obey Ohm’s law over the entire range of applied voltages? Give reasons based on your graph.

Related theory

Browse the problem library