Light with a wavelength of 3.9 x 10-7 m is used in a double slit experiment. The screen is placed 1.00 m from the slits and the first order line is found 0.0655 m from the central bright spot. What is the separation between the slits?

Group of answer choices

7.63 x 10-6 m

5.95 x 10-6 m

4.66 x 10-6 m

9.66 x 10-6 m

1 answer

To find the separation between the slits in a double-slit experiment, we can use the formula for the position of bright spots (fringes) on the screen:

\[ y_m = \frac{m \lambda L}{d} \]

Where:

  • \( y_m \) is the position of the m-th order bright spot from the central maximum,
  • \( m \) is the order of the bright spot (for the first order, \( m = 1 \)),
  • \( \lambda \) is the wavelength of the light,
  • \( L \) is the distance from the slits to the screen,
  • \( d \) is the separation between the slits.

From the problem:

  • \( y_1 = 0.0655 , \text{m} \) (first order fringe),
  • \( \lambda = 3.9 \times 10^{-7} , \text{m} \),
  • \( L = 1.00 , \text{m} \),
  • \( m = 1 \).

Plugging in the values for the first-order bright spot:

\[ 0.0655 = \frac{1 \cdot (3.9 \times 10^{-7}) \cdot 1.00}{d} \]

Now we can solve for \( d \):

\[ d = \frac{(3.9 \times 10^{-7}) \cdot 1.00}{0.0655} \]

Calculating this:

\[ d = \frac{3.9 \times 10^{-7}}{0.0655} \approx 5.95 \times 10^{-6} , \text{m} \]

Thus, the separation between the slits is approximately \( 5.95 \times 10^{-6} , \text{m} \).

Therefore, the correct answer is:

5.95 x 10-6 m