**Double Slit Experiment**

The double slit experiment is a classic experiment in physics that demonstrates the wave-particle duality of light. In this experiment, a beam of light is passed through two narrow slits and the resulting interference pattern is observed on a screen.

**Interference Pattern**

When light passes through the slits, it diffracts and creates a pattern of alternating bright and dark spots on the screen. This pattern is known as an interference pattern and is a result of the superposition of the waves from the two slits.

**Calculating the Angle**

To calculate the angle at which the third order bright spot, the second minimum from the central maximum, is observed, we can use the formula for the angle of the nth order bright spot:

θ = nλ / d

where θ is the angle, n is the order of the bright spot, λ is the wavelength of light, and d is the distance between the slits.

In this case, the wavelength of light is given as 480nm and the distance between the slits is given as 0.05cm.

Converting the wavelength to meters:
480nm = 480 x 10^-9m

Converting the distance between the slits to meters:
0.05cm = 0.05 x 10^-2m

Substituting the values into the formula:
θ = (3 x 480 x 10^-9m) / (0.05 x 10^-2m)

Calculating the angle:
θ = 0.0144 radians

Converting the angle to degrees:
θ = 0.0144 radians x (180 / π) degrees

θ ≈ 0.826 degrees

Therefore, the third order bright spot, the second minimum from the central maximum, will be observed at an angle of approximately 0.826 degrees from the straight through beam.

**Explanation**

The interference pattern observed in the double slit experiment is a result of the constructive and destructive interference of the waves from the two slits. The bright spots correspond to regions of constructive interference, where the waves from the two slits reinforce each other, while the dark spots correspond to regions of destructive interference, where the waves from the two slits cancel each other out.

The angle at which the bright spots are observed depends on the wavelength of light and the distance between the slits. As the order of the bright spot increases, the angle at which it is observed also increases. This is because the path difference between the waves from the two slits increases with increasing order, leading to a larger phase difference and a larger angle of observation.

In this case, the third order bright spot, the second minimum from the central maximum, is observed at an angle of approximately 0.826 degrees. This means that the waves from the two slits interfere destructively at this angle, resulting in a dark spot. The second minimum is observed because the first minimum is located at a larger angle.