In a four-slit experiment the distance between the central bright fringe and the second off-center bright fringe is 8 cm. What is the distance between adjacent dark fringes?

y’= 2 cm

Explanation:

In the system with more than two slits we can consider them a network and diffraction, which is described by the expression

               d sin θ = m λ

Where d is the separation between the slits, λ the wavelength and m an integer that is the order of diffraction.

Let's use trigonometry for line separation

            tan θ = y / L

Where L is the distance to the observation screen, in diffraction and measured angle experiments it is small

            tan θ = sin θ / cos θ = sin θ

We replace

            d y / L = m λ

This is the equation for constructive interference, it indicates that y = 8 cm for m = 2

           d 8 / L = 2 λ

           d / Lλ = 2/8

For the case destructive interference we must increase the length is wave is λ/2, the equation remains

           d y’/ L = (m + ½) λ

In the case of adjacent strips m = 0

          d y’/ L = (0+ 1/2) λ

          d / Lλ = 1 / 2y’

Let's match the two diffraction equations

                 ¼ = 1 / 2y’

                2y’= 4

                y’= 2 cm

answer: the exterior temperature of commercial jet planes as they leave the stratosphere and return to the ground increases steadily.

explanation:

the lower most layer of atmosphere is troposphere which extends from 0 to 12 km above the surface of the earth. the temperature initially decreases as distance is increased from the earth's surface. commercial jets fly in lower part of the stratosphere. the stratosphere extends upto 50 km. the temperature in stratosphere starts rising again due to presence of ozone which traps the uv rays.

thus, when the planes leave the stratosphere and return to the ground, the exterior temperature increases steadily.

a and c

c is 100% but i am confused in a