Tag: electric current through conductors

Questions Related to electric current through conductors

The carbon resistor has three orange bands. The maximum value of resistance offered by the resistor will be __________.

physics electric current through conductors carbon resistance and colour codes for carbon resistance carbon resistors and their colour coding resistors

  1. $39.6k\Omega $

  2. $49.6k\Omega $

  3. $33k\Omega $

  4. $26.4k\Omega $

Show answer
Correct Option: C
Explanation:
The resistance can be calculated with a help of the colour coding chart.
The colour of the first band indicates the first significant figure, the colour of the second band indicates the second significant figure and the colour of the third band indicates the multiplier to be used. 
Thus, the resistance of a carbon resistor with three orange bands would be:
3 (orange) 3(orange) x 1000 (orange) = 33,000 ohms

The maximum value of resistance $=33\times { 10 }^{ 3 }\Omega =33k\Omega $

Brown, Red and Orange coloured bands on a Carbon resistor are followed by silver band. The value of resistor is ________

physics electric current through conductors carbon resistance and colour codes for carbon resistance carbon resistors and their colour coding resistors

  1. $320\Omega \pm 5$%

  2. $12k\Omega \pm 5$%

  3. $320\Omega \pm 10$%

  4. $12k\Omega \pm 10$%

Show answer
Correct Option: D
Explanation:

The Color Coding of the resistances is given by:


Black     Bown     Red     Orange    Yellow      Green     Blue     Violet     Grey     White
     0           1            2           3              4              5             6            7           8              9

Tolerance:
Gold     Silver     No color
    5%        10%         20%

So, according to the color-coding, 
$R=AB\times10^C \pm D$

Here, A is the first color, B is the second color, C is the third color and D is the strip of the tolerance.

So $R=12\times 10^3\pm10\%$

$\implies12k\Omega\pm10\%$

So option $D$ is correct.

Blue,green,yellow and yellow is the color band on the resistor,find its resistance?

physics electric current through conductors carbon resistance and colour codes for carbon resistance carbon resistors and their colour coding resistors

  1. $(75\times 10^4 )\Omega \pm 5$%

  2. $(65\times 10^4 )\Omega \pm 5$%

  3. $(52\times 10^4 )\Omega \pm 5$%

  4. $(65\times 10^4 )\Omega \pm 10$%

Show answer
Correct Option: B
Explanation:

The first two colours are blue and green.


For first two significant digits we need to consider digits signified by first two colours.
And, blue colour signifies $6$, and green colour signifies $5$.
And for multiplier the third colour is considered which is here yellow meaning $10^4$.

And, for tolerance , fourth colour is given yellow meaning $5\%$.

Hence resistance is $ (65\times 10^4)\Omega \pm5\%$

Answer-(B)

The order of coloured rings in a carbon resistor is red, yellow, blue and silver. The resistance of the carbon resistor is :

physics electric current through conductors carbon resistance and colour codes for carbon resistance carbon resistors and their colour coding resistors

  1. $24\times 10^6\ \Omega \pm 5\%$

  2. $24\times 10^6\ \Omega \pm 10\%$

  3. $34\times 10^4\ \Omega \pm 10\%$

  4. $26\times 10^4\ \Omega \pm 5\%$

Show answer
Correct Option: B
Explanation:

According to colour code of carbon resistors, red stands for $2$, yellow for $4$, blue for $6$ and silver stands for $5$%.
First and second band represents the first two significant figure of resistance.
Third band represents the power raised to $10$ in the value of resistance.
Fourth band represents the tolerance.
Thus resistance of given carbon resistor is  $24\times 10^{6} \ \Omega$
Tolerance in the resistance is $10%$.
Thus resistance is  $24\times 10^6 \Omega  \ \pm 10$%

A resistance of 600$\Omega$ has the color code given by 3 steps. The color of strips (from left to right) is given by

physics electric current through conductors carbon resistance and colour codes for carbon resistance carbon resistors and their colour coding resistors

  1. blue, black & brown

  2. blue, brown & black

  3. brown, blue & black

  4. brown, black & blue

Show answer
Correct Option: A
Explanation:

Resistor Band Colors

As shown above, a carbon-composition resistor can have 4 to 6 bands. A 5-band resistor is more precise compared to a 4-band type because of the inclusion of a third significant digit. A 6-band resistor is like a 5-band resistor but includes a temperature coefficient band (the 6th band). 

|   | 4-band | 5-band | 6-band | | --- | --- | --- | --- | | 1st band | 1st significant digit | 1st significant digit | 1st significant digit | | 2nd band | 2nd significant digit | 2nd significant digit | 2nd significant digit | | 3rd band | multiplier | 3rd significant digit | 3rd significant digit | | 4th band | tolerance | multiplier | multiplier | | 5th band | N/A | tolerance | tolerance | | 6th band | N/A | N/A | temperature coefficient |

Each color represents a number if it's located from the 1st to 2nd band for a 4-band type or 1st to 3rd band for a 5-band and 6-band type. 

| Color | Value | | --- | --- | | Black (2nd and 3rd bands only) | 0 | | Brown | 1 | | Red | 2 | | Orange | 3 | | Yellow | 4 | | Green | 5 | | Blue | 6 | | Violet | 7 | | Grey | 8 | | White | 9 |

 

Mnemonics were created to easily memorize the sequence of the colors. The most popular mnemonic is "Big Boys Race Our Young Girls But Violet Generally Wins" where the first letter of each word corresponds to the first letter of the color. 

If the color is found on the 3rd band for a 4-band type or the 4th band for a 5-band and 6-band type, then it's a multiplier.

| Color | Value | | --- | --- | | Black | x1 | | Brown | x10 | | Red | x100 | | Orange | x1000 | | Yellow | x10000 | | Green | x100000 | | Blue | x1000000 | | Violet | x10000000 | | Grey | x100000000 | | White | x1000000000 |

Notice that the number of zeroes is equal to the color's number as per the previous table.

The fourth band (or 5th for the 5-band and 6-band) indicates the tolerance values. Here, two colors are added (gold and silver).

| Color | Value | | --- | --- | | Black | N/A | | Brown | ±1% | | Red | ±2% | | Orange | ±3% | | Yellow | ±4% | | Green | ±0.5% | | Blue | ±0.25% | | Violet | ±0.10% | | Grey | ±0.05% | | White | N/A | | Gold | ±5% | | Silver | ±10% |

The 6th band for a 6-band type resistor is the temperature coefficient. This indicates how much the actual resistance value of the resistor changes when the temperature changes.

| Color | Value | | --- | --- | | Black | N/A | | Brown | 100 ppm/ºC | | Red | 50 ppm/ºC | | Orange | 15 ppm/ºC | | Yellow | 25 ppm/ºC | | Green | N/A | | Blue | 10 ppm/ºC | | Violet | 5 ppm/ºC | | Grey | N/A | | White | N/A |

 

Color Code Exceptions

5 Band Resistor with a 4th Band of Gold or Silver

Five band resistors with a fourth band of silver or gold form an exception, and are utilized on specific or older resistors. The first two bands represent the significant digits, the third band is a multiplication factor, the fourth band is for tolerance and the fifth band is for the temperature coefficient (ppm/K).

The colour code of a carbon resistor is, Brown, Black, Brown and Red. The value of the resistor is?

physics electric current through conductors carbon resistance and colour codes for carbon resistance carbon resistors and their colour coding resistors

  1. $10\Omega \pm 5\%$

  2. $1k\Omega \pm 2\%$

  3. $100\Omega \pm 2\%$

  4. $10\Omega \pm 2\%$

Show answer
Correct Option: C
Explanation:

According to the colour code, brown colour stands for $1$, black for $0$ and red for  $2$.
First and second band represents the first and second significant number respectively.
So, it is  $10\Omega$.
Third band represents power of $10$ by which it is raised, so it is  $10^1$.
Last band represents the tolerance of resistor, so it is  $2$%.
Thus value of resistance,   $R = (10\times 10^1)\Omega \pm 2$% $ = 100\Omega \pm 2$%

A resistor is marked with the rings coloured brown, black, green and gold. The resistance in ohm is?

physics electric current through conductors carbon resistance and colour codes for carbon resistance carbon resistors and their colour coding resistors

  1. $(3.5\times 10^5\pm 5\%)$

  2. $(1.10\times 10^5\pm 10\%)$

  3. $(8\times 10^6\pm 5\%)$

  4. $(1\times 10^6\pm 5\%)$

Show answer
Correct Option: D
Explanation:
By color coding
Brown Black Green Gold
$1             .0   \times10^6 \pm5\%$