Question

What is the value of the current flowing through a 5ohm resistor and a voltage source of 10V?
A) Zero ohm
B) 0.5 ohm
C) 2 ohm
D) 5 ohm

Answer 1

Hint: To solve the above problem we will use Ohm’s Law, which tells us about the linear relationship between the voltage and current.
V=IR (V is the voltage, I is the current and R is the resistance).
With the help of the above relation we will find the current flowing through the 5 ohm resistor.

Complete step by step answer:
Ohm’s law states that:
Current through a conductor between two points is directly proportional to the voltage across the two points.
$ \Rightarrow $ V ∝ I
$ \Rightarrow $ V=RI, where R is the constant of proportionality here as resistance.
A real life example of Ohm’s law is: When we run the mixer in our household chores we increase the speed of the mixer by pressing the high or medium button from low. The increase in speed depends on the decrease in resistance and increase in current (because current is inversely proportional to resistance).
Now, come to the calculation part.
$
   \Rightarrow V = IR \\
   \Rightarrow I = \dfrac{V}{R} \\
   \Rightarrow I = \dfrac{{10}}{5} \\
   \Rightarrow I = 2ohm \\
 $ (we use the formula we have mentioned in the hint and substituted the values)
Thus, current flowing in the 5ohm resistor is 2A.
Option C is correct.

Note: Conductivity and resistivity of a conductor are inversely proportional to each other, when resistivity of a material decreases its conductivity increases and when resistivity of a material increases its conductivity decreases. The best example of decreasing resistivity is photosensitive resistor or light dependent resistor.