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Two Resistance A and B have Colour Codes
By BYJU'S Exam Prep
Updated on: September 25th, 2023
Two resistors, a and b, have colour codes: orange, blue, white, brown, red, and green. Then the ratio of their resistances a:b is
A. 3:1
B. 1:3
C. 3×104 :1
D. 1:3×104
Select the correct answer from the above-given options
Table of content
Answer: C. 3×104 :1
Two resistors, a and b, have colour codes: orange, blue, white, brown, red, and green. Then the ratio of their resistances a:b is 3×104 :1.
Solution:
Resistor colour coding uses coloured bands printed on the resistor body to calculate the resistance value.
Generally, there will be 3, 4 and 5 colour band resistors; each colour band position and colour will have a particular specification significant value.
The first two colour bands indicate significant value; the third band will indicate multiplier value.
The fourth band indicates the tolerance if present, and if not, the tolerance of that resistor will be 20%.
If present, the fifth band indicates the resistor’s temperature coefficient. And Colour coding and its values are shown below table.
Colour |
Digit |
Multiplier |
Tolerance |
Black |
0 |
1 |
|
Brown |
1 |
101 |
1% |
Red |
2 |
102 |
2% |
Orange |
3 |
103 |
|
Yellow |
4 |
104 |
|
Green |
5 |
105 |
0.5% |
Blue |
6 |
106 |
0.25% |
Violet |
7 |
107 |
0.1% |
Grey |
8 |
108 |
0.05% |
White |
9 |
109 |
|
Gold |
|
5% |
|
Silver |
|
10% |
|
None |
|
20% |
So, from the above information, we can calculate the resistance value of resistors a and b.
Resistance of a:
Given colour coding for resistor a: orange, blue, white
So, the resistance of a =36×109 Ω
Resistance of b:
Given colour coding for resistor b: brown, red, green
So, the resistance of b =12×105 Ω
The ratio of resistances a and b =36×109:12×105 =3×104:1
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