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(a) How fast must you be approaching a red traffic light(λ=675nm) for it to appear yellow (A=575nm)? Express your answer in terms of the speed of light. (b) If you used this as a reason not to get a ticket for running a red light, how much of a fine would you get for speeding? Assume that the fine is$1.00 for each kilometer per hour that your speed exceeds the posted limit of 90km/h.

Short Answer

Expert verified

The red traffic light moving with 0.159c speed of light and the fine is 1.72×108milliondollar.

Step by step solution

01

Definition of frequency

The term frequency may be defined as the number of times something happens in a particular time period.

02

Determine the red-light moving speed and price of ticket.

The moving speed of red light can be calculated by the relation

u=cf2-f02f02+f2

Now solving forf,f0

f=cλyellowf=2.998×108m/s575×10-9mf=5.21×1014Hzf=cλyellowf0=2.998×108m/s675×10-9mf0=4.44×10-9Hz

Now put both values in above result than

u=c5.21×1914Hz2-4.44×1014Hz24.44×1014Hz2-5.21×1914Hz2u=0.159c

Hence, the red traffic light moving with 0.159c speed of light.

Now for the ticket price

0.159c=0.159(3×105km/s)0.159c=(4.77×104km/s)3600s1h0.159c=1.72×108Km/h

Hence, the fine is$1.72×108 dollar.

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