Discussion :: Transformers  General Questions (Q.No.19)
19.  To step 120 V ac up to 900 V ac, the turns ratio must be 

Answer: Option C Explanation: No answer description available for this question.

Abby Joseph said: (Dec 15, 2010)  
N2/N1=K=V2/V1 Here V1 is 120, V2 is 900 so K=900/120=7.5 
Ahmed Al Rawas said: (May 20, 2011)  
Why shouldn't be N1/N2 = v1/v2 thus, N1/N2 = 120/900 = .133 isn't that right ?? 
Ambrish said: (Jul 7, 2011)  
Yeah my doubt is also same ? 
Murugaperumal said: (Aug 10, 2011)  
It is step up transformer so, N2/N1=V2/V1, N2/N1=900/120, N2/N1=7.5. 
Pruthvi said: (Aug 15, 2011)  
Is turns ratio different for step up and step down transformer? 
Mahijagadeesh said: (Sep 2, 2011)  
Turns ratio means the ratio of primary turns to secondary turns is it wrong? But why in this problem took reverse. 
Yogesh Sabota said: (Nov 4, 2011)  
I agree with Mahijagadeesh this answer is incorrect It should be 0.13v 
Asim Juneja said: (Jan 22, 2012)  
N2/N1 is transformation ratio while, N1/n2 is turns ratio, thus my perception says correct ans. is 0.13 
Mahesh Pakki said: (Mar 26, 2012)  
Guys ... please remeber for step down transformer , turns ratio < 0 Step up transformer , turns ratio > 0 .. In this question .. its step up .. hence turns ratio should be greater then zero .. 
Sirisha said: (May 24, 2012)  
Turns ratio=N1/N2. (step down). Turns ratio=N2/N1. (step up). If not mentioned the type of tx by default consider step up. 
Amarjyoti Sarmah said: (Aug 15, 2013)  
Is turns ratio different for step up and step down transformer? N2/N1 is transformation ratio while, N1/N2 is turns ratio, Is not it right. I am very much confused. Please help me? 
Naveed said: (Oct 20, 2013)  
The ratio of a fourtoone stepdown transformer is written as 4:1.The ratio of a onetofour stepup transformer should be written as 1:4. Notice in the two ratios that the value of the primary winding is always stated first. 
Rajan India said: (Mar 16, 2015)  
Turns ratio k = v2/v1. Here, k = Turns ratio of transformer. v2 = Secondary voltage of transformer. v1 = Primary voltage of transformer. 
Vicky said: (Jan 3, 2016)  
Turns ratio means ratio of high voltage side to low voltage side turns. 
Stuti Kushwaha said: (Feb 16, 2016)  
Please help me that where we can use n1/n2 and where we can use n2/n1? 
Mehaboob Nadaf said: (Mar 20, 2016)  
N2/N1 = V2/V1. 900/120 = K=7.5. 
San said: (Mar 24, 2016)  
Is it same for V2/V1, R2/R1 & I1/I2? 
Raghuvamsi said: (Apr 29, 2016)  
Yes, @Ahmed. The answer should be 0.13. Here the problem is asking turns ratio, not transformation ratio. 
Ramesh said: (Jun 16, 2016)  
Finally, what is the correct answer? 
Ajit said: (Nov 22, 2016)  
Yes, I agree the answer is 0.13. 
Sanjay Patil said: (Nov 24, 2016)  
Yes, Agree with the answer 0.13. Because N2/N1= V2/V1= I1/I2 it is transformation ratio and N1/N2 is Turn Ratio. 
Teja said: (Jun 20, 2017)  
Turns ratio is primary to secondary. So the answer is wrong. 
Aditya Singh said: (Apr 14, 2018)  
Yes, the answer should be 0.13. 
Ankita Mali said: (Dec 23, 2018)  
What is the final answer? Please tell me. 
Shivam said: (Sep 29, 2019)  
Answer will be 0.13. Because turn ratio is inverse of transformation ratio. 
Sayan Paul said: (Nov 2, 2020)  
0.133. 
Abhinaya said: (Apr 15, 2021)  
I agree with 0.13 the 7.5 is k. Turns ratio = 1/K, 1/7.5 = 0.13. 
Srinivas Reddy said: (Jul 5, 2021)  
To step up by means N2/N1 high voltage to low and step down N1/N2. 
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