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Question
Find the time required for a 50 Hz alternating current to change its value from zero to the rms value.
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Solution
Data: f = 50 Hz, i = `"i"_0/sqrt2` ∴ `"i"/"i"_0 = 1/sqrt2`
i = i0 sin ωt
∴ `sin omega "t" = "i"/"i"_0 = 1/sqrt2`
∴ ωt = `pi/4` rad
∴ `2pi"ft" = pi/4`
∴ t = `1/("8f") = 1/(8(50)) = 1/400`
`= (1000 xx 10^-3)/400 = 2.5 xx 10^-3`s
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