In a step up transformers, `220V` is converted into `200V`. The number of turns in primary coil is `600`. What is the number of turns in the secondary coil?

Options

A. `60`
B. `600`
C. `6000`
D. `100`

Explanation

To solve the problem, we will use the transformer equation which relates the number of turns in the primary and secondary coils to the voltages across them. The equation is given by:

\[ \frac{N_s}{N_p} = \frac{V_s}{V_p} \]

Where:
- \(N_s\) = number of turns in the secondary coil
- \(N_p\) = number of turns in the primary coil
- \(V_s\) = voltage in the secondary coil
- \(V_p\) = voltage in the primary coil

### Step 1: Identify the given values
- \(V_p = 220V\) (voltage in the primary coil)
- \(V_s = 200V\) (voltage in the secondary coil)
- \(N_p = 600\) (number of turns in the primary coil)

### Step 2: Substitute the known values into the transformer equation
We can rearrange the transformer equation to solve for \(N_s\):

\[ N_s = N_p \cdot \frac{V_s}{V_p} \]

Substituting the known values:

\[ N_s = 600 \cdot \frac{200}{220} \]

### Step 3: Calculate the value of \(N_s\)
Now, we will perform the calculations:

\[ N_s = 600 \cdot \frac{200}{220} = 600 \cdot \frac{20}{22} = 600 \cdot \frac{10}{11} \]

Calculating this:

\[ N_s = 600 \cdot 0.9091 \approx 545.45 \]

### Step 4: Round the result
Since the number of turns must be a whole number, we round \(545.45\) to the nearest whole number:

\[ N_s \approx 545 \]

### Final Answer:
The number of turns in the secondary coil is approximately **545 turns**.

---