The pole strength of a bar magnet of magnetic moment 5`Am^(2)` and geometric length 6 cm is

Options

A. `10AM`
B. 100 Am
C. 1000 Am
D. `1AM`

Explanation

To find the pole strength of a bar magnet given its magnetic moment and geometric length, we can follow these steps:

### Step 1: Understand the relationship between magnetic moment, pole strength, and magnetic length.
The magnetic moment (M) of a bar magnet is given by the formula:
\[ M = P \times L \]
where:
- \( M \) is the magnetic moment,
- \( P \) is the pole strength,
- \( L \) is the magnetic length of the magnet.

### Step 2: Identify the given values.
From the question, we have:
- Magnetic moment \( M = 5 \, \text{Am}^2 \)
- Geometric length \( L_g = 6 \, \text{cm} \)

### Step 3: Convert geometric length to magnetic length.
The magnetic length \( L \) is related to the geometric length \( L_g \) by the formula:
\[ L = \frac{5}{6} L_g \]
Substituting the given geometric length:
\[ L = \frac{5}{6} \times 6 \, \text{cm} = 5 \, \text{cm} \]

### Step 4: Convert the magnetic length from centimeters to meters.
Since we need to work in SI units, we convert:
\[ L = 5 \, \text{cm} = 5 \times 10^{-2} \, \text{m} = 0.05 \, \text{m} \]

### Step 5: Rearrange the formula to find pole strength.
Now, we can rearrange the formula for magnetic moment to solve for pole strength \( P \):
\[ P = \frac{M}{L} \]

### Step 6: Substitute the values into the equation.
Now substituting the values we have:
\[ P = \frac{5 \, \text{Am}^2}{0.05 \, \text{m}} \]

### Step 7: Calculate the pole strength.
Calculating the above expression:
\[ P = \frac{5}{0.05} = 100 \, \text{A} \]

### Final Answer:
The pole strength of the bar magnet is \( 100 \, \text{A} \).

---