Question

How many ohms is the resistance of the bulb

Answer 1

2Ω. Based on the graph the resistance of the bulb is 2Ω.

Based on the graph of the image we can see there are a linear proportionality between the voltage and the current. So, we can modeling this problem calculating the slope of the straight line in the graph as follow:

We can write a formula of the form
`m=(y_(1)-y )/(x_(1)-x)`.

From the Ohm's Law we know that the resistance is directly proportional to the voltage and inversely proportional to the current
`R = (V)/(I)`.

From the graph we can see in the x-axis the values of the voltage and the y-axis the value of the current, with the points (x, y) = (2, 1) and (x₁, y₁) = (4, 2) marked in the graph, we can write:

`m=(y_(1)-y )/(x_(1)-x)`

`m=(2A - 1A)/(4V - 2V)`

We need to express the equation
`m=(2A - 1A)/(4V - 2V)` in the form
`R = (V)/(I)`:

`R = (1)/(m)=(1)/((2A - 1A)/(4V - 2V)) \\R = (4V - 2V)/(2A - 1A)}\\R = (2V)/(1A)`

R = 2Ω