To find the distance d over which a signal can be seen clearly in foggy conditions, a railways engineer uses…

To find the distance d over which a signal can be seen clearly in foggy conditions, a railways engineer uses dimensional analysis and assumes that the distance depends on the mass density ρ of the fog, intensity (power/area) S of the light from the signal and its frequency f. The engineer finds that d is proportional to S1n . The value of n is

Solution

dρxSyFz
LML-3xMT-3yT-1z
x+y=0, -3x=1, -3y-z=0
x=-13, y=13, z=-1
y=1n
n=3 `

Asked in: JEE Advanced 2014 (Paper 1)

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