The value of e/m for an electron is

Options

A. `1.78 xx 10^(8) c//g`
B. `1.6724 xx 10^(-24) c//g`
C. 0.005486 c/g
D. 1.00866 c/g

Answer

To find the value of e/m (the charge-to-mass ratio) for an electron, we can follow these steps:

### Step 1: Identify the charge of an electron (e)
The charge of an electron is approximately:
\[ e = 1.6 \times 10^{-19} \text{ coulombs} \]

### Step 2: Identify the mass of an electron (m)
The mass of an electron is approximately:
\[ m = 9.31 \times 10^{-31} \text{ kg} \]

### Step 3: Calculate the charge-to-mass ratio (e/m)
The charge-to-mass ratio can be calculated using the formula:
\[ \frac{e}{m} = \frac{1.6 \times 10^{-19} \text{ C}}{9.31 \times 10^{-31} \text{ kg}} \]

### Step 4: Perform the calculation
Now, we can perform the calculation:
\[ \frac{e}{m} = \frac{1.6 \times 10^{-19}}{9.31 \times 10^{-31}} \approx 1.758 \times 10^{11} \text{ C/kg} \]

### Step 5: Convert to C/g (if needed)
If we want to express this in coulombs per gram, we can convert kilograms to grams (1 kg = 1000 g):
\[ \frac{e}{m} \approx \frac{1.758 \times 10^{11} \text{ C/kg}}{1000} = 1.758 \times 10^{8} \text{ C/g} \]

### Final Answer
Thus, the value of e/m for an electron is approximately:
\[ 1.758 \times 10^{11} \text{ C/kg} \]
or
\[ 1.758 \times 10^{8} \text{ C/g} \]

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