How Does a Calor Engine Power a 200V Generator at Different RPMs?

[wiraimperia]

Homework Statement

Hello, let me introduce myself first. I am Wira, a Senior High School alumnus in Indonesia. I am currently preparing for my university entrance exam. This is a problem which I get stuck in, and can you help me with it?

Indonesian:
Suatu mesin kalor yang bekerja dengan siklus yang dibangun dari dua isobar dan dua isokhor seperti pada gambar di atas digunakan untuk menggerakkan sebuah generator yang tegangan keluarannya 200V. Apabila generator ini mendapat beban arus 4A, maka mesin kalor tersebut dijalankan pada putaran per menit...
A 360 rpm
B 400 rpm
C 440 rpm
D 480 rpm
E 520 rpm
English:
A calor engine that works with the cycle of two isobarics and two isochorics shown in the picture above is used to spin a generator that has the output potential of 200V. If this generator has the current of 4A, then that engine is used in ... rpm
(Options above)

Homework Equations

V = NBAw sin (wt)
E = V I t
E = The area of the box area in the graph

The Attempt at a Solution

I have tried using:
V = NBAw sin (wt)
Consider that sin (wt) = 1
But we have no data of N and B...
And for the cycle
Energy generated = the area of the box
Energy = Energy
Consider that t = 1
V I t = NBAw sin (wt)
NBAw I = (Box area)
We are looking for the w, so it becomes
w = (Box area)/NBA
I got stuck in this...
Do you have any ideas? Your contribution helps improve me. =)

 

[ehild]

You are given the voltage and current of the generator, so you know its power. (You can assume that the load is ohmic so current and voltage are in phase.)

Calculate the work produced by one cycle of the heat engine. With how many cycles do you get the desired power?

ehild