A galvanometer coil has a resistance of `990Omega` and it shows full scale deflection for a current of 10mA. Calculate the value of resistance required to convert it into an ammeter of range 1 A.

Explanation

To convert a galvanometer into an ammeter, we need to add a shunt resistance in parallel with the galvanometer. Here’s how to calculate the required shunt resistance step by step:

### Step-by-Step Solution:

1. **Identify the given values:**
- Resistance of the galvanometer coil, \( R_g = 990 \, \Omega \)
- Full-scale deflection current of the galvanometer, \( I_g = 10 \, \text{mA} = 0.01 \, \text{A} \)
- Total current to be measured by the ammeter, \( I = 1 \, \text{A} \)

2. **Determine the current through the shunt resistance:**
- The current through the shunt resistance, \( I_s \), can be calculated using the formula:
\[ I_s = I - I_g \]
- Substituting the values:
\[ I_s = 1 \, \text{A} - 0.01 \, \text{A} = 0.99 \, \text{A} \]

3. **Use the formula for shunt resistance:**
- The formula for the shunt resistance \( R \) is given by:
\[ R = \frac{I_g \cdot R_g}{I_s} \]
- Substituting the known values:
\[ R = \frac{0.01 \, \text{A} \cdot 990 \, \Omega}{0.99 \, \text{A}} \]

4. **Calculate the shunt resistance:**
- Performing the calculation:
\[ R = \frac{9.9 \, \Omega}{0.99} = 10 \, \Omega \]

5. **Conclusion:**
- The required shunt resistance to convert the galvanometer into an ammeter of range 1 A is \( R = 10 \, \Omega \).