A capacitor with a capacitance of C = 25.7 μF is slowly charged by a constant current of I = 45.7 nA. How long does it take to charge the capacitor to a voltage of V = 29.4 V?

To calculate the time it takes to charge a capacitor, we can use the formula:

t = Q / I

Where:
t = time (in seconds)
Q = charge (in coulombs)
I = current (in amperes)

To find the charge Q, we can use the formula:

Q = C * V

Where:
Q = charge (in coulombs)
C = capacitance (in farads)
V = voltage (in volts)

Given:
C = 25.7 μF = 25.7 * 10^(-6) F
I = 45.7 nA = 45.7 * 10^(-9) A
V = 29.4 V

First, let's calculate the charge Q:

Q = C * V
Q = (25.7 * 10^(-6)) * 29.4
Q = 0.00075438 C

Now, we can calculate the time t:

t = Q / I
t = 0.00075438 / (45.7 * 10^(-9))
t = 16,499.34 seconds

Therefore, it takes approximately 16,499.34 seconds to charge the capacitor to a voltage of 29.4 V.