**1. The problem statement, all variables and given/known data**

The time constant of charging for the capacitor shown in the figure is

**2. Relevant equations**

See attached diagram

**3. The attempt at a solution**

[itex]\tau = R_{eq} C [/itex]

[itex]R_{eq} = R/2 [/itex]

So the answer should be t= RC/2. But the correct answer is 0! :confused:

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