Question

The colour code for a resistor of resistance $3.5$k $\Omega$ with $5\%$ tolerance is:
A. Orange, green, orange and gold
B. Red, yellow, black and gold
C. Orange, green, orange and silver
D. Orange, green, red and silver
E. Orange, green, red and gold

Answer 1

Colour coding of resistors are colour bands to quickly identify the value of resistance of the resistor along with its percentage of tolerance. To solve these types of questions we first need to remember the colours associated with different values of resistor.

Complete step by step answer:
Given: Resistance, $R = 3.5\Omega and Tolerance =$5% $.
Step by step solution:
-The above question is an example of 4 band code

Colour code table:

Colour	Digit	multiplier	Tolerance (%)
Red	0	${10^0}$
Brown	1	${10^1}$	1
Red	2	${10^2}$	2
Orange	3	${10^3}$
Yellow	4	${10^4}$
Green	5	${10^5}$	0.5
Blue	6	${10^6}$	0.25
Violet	7	${10^7}$	0.1
Grey	8	${10^8}$
White	9	${10^9}$
Gold		${10^{ - 1}}$	5
Silver		${10^{ - 2}}$	10
none			20

So the resistance with tolerance can be written as: $R = 3.5\Omega \pm 5\%$. Therefore the colour code will be: orange, green, red and gold.

So option D is correct.

Note: In the resistors of large values where there is enough space for typing the information such as the resistance value, tolerance and wattage rating are printed on them. But in case of small resistors where there is not enough space for typing, colour codes are used to represent the specifications.