Question

A carbon resistor has three bands of brown, black and green in order. What will be the range of resistance it offers.
A) $$7 \times {10^5}\Omega - 13 \times {10^5}\Omega $$
B) $$9 \times {10^5}\Omega - 11 \times {10^5}\Omega $$
C) $$8 \times {10^5}\Omega - 12 \times {10^5}\Omega $$
D) None of these

Answer 1

Hint: In the color coding of a carbon resistor every color signifies a fixed value. The first band depicts the 1st value and second color depicts the second value. And the third band represents the power of extent.

Complete step by step answer:
The given carbon resistor has three bands brown, black and green. Brown represents value 1, black represents value 0 and green represents 4. So according to their order the value of the carbon resistor should be around $$9 \times {10^5}\Omega - 11 \times {10^5}\Omega $$. These color coding is used to identify the value of carbon resistor easily. Generally carbon resistors have 4 to 5 bands. Where the last band represents the tolerance of the resistor.

The tolerance is the order of which the value of resistance can be more or less then the given value. The color coding proved to be a significant method for determining the value of carbon resistors. There are other methods also but this method is quite easy. These resistors are not available in values commercially. Only fixed values of resistances are available.

Note: There are only 3 bands in the given resistor. That doesn’t mean the coding is wrong. Here the last band is of no color. The no color band represents the tolerance of 20%. Also the range of resistance is 20% upper and 20% lower.