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Question:

A ray of light along x + √3y = √3 gets reflected upon reaching the x-axis. Equation of the reflected ray is?

y = √3x - √3

√3 y = x - √3

√3 y = x + 1

y = x + √3

Solution:

The given equation of the incident ray is x + √3y = √3.
The slope of this line is m1 = -1/√3.
When the ray reflects from the x-axis, the angle of incidence is equal to the angle of reflection. The reflected ray will have a slope m2 such that the angle it makes with the x-axis is equal to the angle the incident ray makes with the x-axis. Therefore, the slope of the reflected ray will be the negative of the slope of the incident ray.
m2 = -m1 = 1/√3
The reflected ray passes through the point (√3, 0), which is the point where the incident ray intersects the x-axis (setting y = 0 in the incident ray equation).
Using the point-slope form of the equation of a line, y - y1 = m2(x - x1), we have:
y - 0 = (1/√3)(x - √3)
y = (1/√3)x - 1
Multiplying by √3 to eliminate the fraction:
√3y = x - √3
Therefore, the equation of the reflected ray is √3y = x - √3