# Electrical Engineering - Voltage, Current and Resistance - Discussion

### Discussion :: Voltage, Current and Resistance - General Questions (Q.No.4)

4.

The minimum resistance value for a blue, gray, red, silver resistor is

 [A]. 612 [B]. 6,120 [C]. 6,800 [D]. 6,460 Explanation:

Because of 10% tolerance(last color silver), this resistance may vary 10% of 6800.

Minimum resistance value = 6800 - 680 = 6120

Maximum resistance value = 6800 + 680 = 7480

 Mani said: (Jan 6, 2011) 6800 right

 Mihir said: (Jan 18, 2011) No the answer is 6120. they have asked for the minimum value. which must be 6800- 10% of 6800. (10% because the 4th color is silver which signifies 10% tolerance)

 Prashant said: (Jan 20, 2011) B B R O Y G B V G W Memorize this colors by the slogan "B B ROY Go to Bombay Via Gate Way of india" and remember the Capital Letters only. Now Starting from first number them starting with 0. So Black = 0 Brown= 1 Red = 2 Orange = 3 And so on. Remember that there are four B in this equation and their order is Black Brown And Blue. => Now the first color of the Resistor is The decimal point. In our CASE it is Blue so it is = 60(Decimal point) => Second one is the Unit point. In our CASE it is Grey so it is = 08(Unit point) Adding that two is now =68 => Third on is the power of 10 and multiply it with the combination of decimal and unit point figure. In our CASE it is Red so it is = 2 Hence it is equal to 10 rest to 2 = 10 ^ 2. So now the Resistance will be 68 * 10 ^ 2 = 6800 Ohms => Now the Last color code is the tolerance hence it is to be introduced in Either in + or in - Formate with the percentage. There are only 3 possible ways for tolerance. Gold = +- 5%; Silver = +- 10% None = +- 20 % In Our Case it is Silver so it is = +- 10 % Finally we got the Resistance value for the given color code is = 6800 +- 10 % => For minimum value substract the 10% of 6800 and or for the maximum value add the 10 % of 6800. In our CASE it is Minimum so 68000 - 10 % of 68000 = 6800 - 0680 = 6120 ohms Ans= B

 Vipul said: (Jan 29, 2011) Option b is correct as we have to consider the tolerance. Of silver that is +/-10%.

 Aramuthan said: (Mar 16, 2011) Answer is wrong . The Answer is Blue = 6 Grey = 8 Red = 2 So 6800 Ohms or 6.8k Ohms Silver is tolerance

 Kalaimani said: (Mar 30, 2011) Ans is "B", because question is minimum resistance value of given color code so it will be ans is "B"

 Kalaimani said: (Mar 30, 2011) blue-6 grey-8 red-2 so value is 6800ohms tolerance +-10% therefore minimum resistance value is 6800/100*10=680 6800-680=6120ohms so ans is "B"

 Nibedita said: (Mar 31, 2011) B is right

 Premshankar Behera said: (Aug 29, 2011) Due to tolerance of 10%, 6800+/-10/100*6800 = 6000 to7600. So according to above mentioned answer 6120 is the lowest value. Hence answer is 6120.

 Ranjeet Kr Singh said: (Nov 15, 2011) As per colour code blue grey red silver 6 8 * 10^2 - 10% so 6800-(6800*10%) = 6800-680 = 6120 ans.

 Veena said: (Dec 24, 2011) Yeah B s correct. As silver has 10% tolerance.

 Sandy said: (Apr 10, 2012) 6120 is the correct answer due to the tolerance of the 10% (silver colour) in the resistance value thus as per general calculation 6800. But 10% of 6800 is 680 thus answer may. 6120 or 7480, here the option available is 6120 thus the answer is 6120.

 Rani said: (Aug 31, 2012) YES ANS B, & thanks to PRASHANT

 Haneef said: (Dec 23, 2012) Blue, gray, red, silver. 68*10^2 (-10%). Tolerance is minimum so substrata if max add. So, (6800/100) *10=680. 6800-680=6120.

 Amit said: (Nov 25, 2013) What is the current of an 208V, 111kW three-phase load with cosFI=0.99 ?

 Nikhil Bhargava said: (Feb 3, 2014) Blue-grey-red-silver, 68*10^2 (-10% tolerance). 6800-(6800*10%). = 6800 - 680. = 6120. Answer is B.

 Mithlesh Pandey said: (Mar 28, 2014) Ya this question all right. The answer is = 6120 is to be correct.

 Prince Dixit said: (Oct 18, 2016) I agree that, 6120 is the right answer.

 Bhadri said: (Nov 24, 2016) I agree with the given answer, i.e. option b.

 Arpit Darji said: (Mar 14, 2017) Thanks for all the given explanation.

 Shashank said: (Aug 10, 2017) What will be the answer if they not ask silver?

 Ejja Rakesh said: (Feb 20, 2020) Thanks, @Prashanth bro for your deep explanation it's better than any other tutor.