An alternating voltage of 50HZ has maximum value of 282.8volts .what time measured from positive maximum value will the instateneous voltage be 141.4

Kwa sababu muda unapimwa kutoka thamani ya juu zaidi chanya, tunatumia kazi ya kosine:
V = V₀ cos(2πft)
Ambapo:
V = voltage ya papo hapo (instantaneous voltage)
V₀ = voltage ya juu zaidi (maximum voltage)
f = marudio (frequency)
t = muda

Tunapewa:
V₀ = 282.8 V
f = 50 Hz
V = 141.4 V

141.4 V = 282.8 V × cos(2π × 50 Hz × t)

cos(2π × 50t) = 141.4 V / 282.8 V
cos(100πt) = 0.5

100πt = arccos(0.5)
Tunajua kuwa arccos(0.5) ni π/3 radians.
100πt = π/3

t = (π/3) / (100π)
t = 1 / (3 × 100)
t = 1 / 300 s

Muda uliopimwa kutoka thamani ya juu zaidi chanya ambapo voltage ya papo hapo itakuwa 141.4 V ni 1/300 sekunde au takriban 0.00333 sekunde.