Why does calculating primary coil current from secondary current give the wrong answer?

[Muhammad Danish]

Homework Statement

Homework Equations

How will we calculate the current in primary coil?

The Attempt at a Solution

The current in the secondary coil will be 2 Amperes by I = V/R. So in the primary coil by using ratio proportion method, the current in the primary coil will be 5 Amperes. But this leads to wrong answer.

 

[SunThief]

Show work for how you come up with 5A for the primary coil current as a starting point...

 

[drvrm]

The current in the secondary coil will be 2 Amperes by I = V/R. So in the primary coil by using ratio proportion method, the current in the primary coil will be 5 Amperes. But this leads to wrong answer.

is there a relation between Vp Vs and Ip , Is ? ultimately they are related to number of turns also.

 

[Muhammad Danish]

Show work for how you come up with 5A for the primary coil current as a starting point...

600V ---- x
240V ---- 2
Since they are directly proportional, we can get x = 5 ampere but I don't think this is a correct answer..

 

[Muhammad Danish]

is there a relation between Vp Vs and Ip , Is ? ultimately they are related to number of turns also.

But number of turns in primary and secondary coil are not mentioned..

 

[drvrm]

By law of conservation of energy - power is conserved in the input and output

Vp . Ip = Vs. Is

.

 

[Muhammad Danish]

By law of conservation of energy - power is conserved in the input and output

Vp . Ip = Vs. Is

.

Oh Thanks, by finding Ip I can find the power dissipated by the formula P = IV right?

 

[Muhammad Danish]

Oh Thanks, by finding Ip I can find the power dissipated by the formula P = IV right?

Just to increase knowledge, where do we use the formula P = V^2/R ?

 

[drvrm]

Just to increase knowledge, where do we use the formula P = V^2
R

its v^2/R
both forms are equivalent...if one is calculating dissipation through load resistance R its good
but how you got 5 amp as current?.