The effictive length of a simple pendulum is the sum of the following three : length of string , radius of bob , and length of hook.
In a simple pendulum experiment , the length of the string , as measured by a meter scale , is `92.0 cm`. The radius of the bob combined with the length of the hook , as measured by a vernier callipers , is `2.15 cm`. The effictive length of the pendulum is

Options

A. a. `94.1 cm`
B. b. `94.2 cm`
C. c. `94.15 cm`
D. d. `94 cm`

Explanation

To find the effective length of a simple pendulum, we need to sum the length of the string, the radius of the bob, and the length of the hook. Let's break down the solution step by step.

### Step 1: Identify the given values
- Length of the string (L) = 92.0 cm
- Combined radius of the bob and length of the hook (R) = 2.15 cm

### Step 2: Write the formula for effective length
The effective length (L_eff) of the pendulum can be calculated using the formula:
\[ L_{eff} = L + R \]
where:
- \( L \) is the length of the string,
- \( R \) is the combined radius of the bob and length of the hook.

### Step 3: Substitute the values into the formula
Now, substitute the values we have into the formula:
\[ L_{eff} = 92.0 \, \text{cm} + 2.15 \, \text{cm} \]

### Step 4: Perform the addition
Now, let's perform the addition:
\[ L_{eff} = 92.0 + 2.15 = 94.15 \, \text{cm} \]

### Step 5: Round the result
Since the question requires us to round the effective length to one decimal place, we round 94.15 cm:
\[ L_{eff} \approx 94.2 \, \text{cm} \]

### Conclusion
Thus, the effective length of the pendulum is approximately **94.2 cm**.