As the frequency of the ac voltage across a capacitor approaches zero, the capacitive reactance of that capacitor:. A) approaches zero.
B) approaches infinity.
C) approaches unity.
D) none of the given answers

B) approaches infinity

Explanation:

The capacitive reactance of an AC capacitor is given by;

Where;

C is the capacitance

f is the frequency of the ac voltage

Therefore, as the frequency of the ac voltage across a capacitor approaches zero, the capacitive reactance of that capacitor approaches infinity.

The correct option is (B) approaches infinity

resonant frequency

the minimum constant speed at which she can catch the train is 2.7 m/s

given:

acceleration = 0.6

time = 4.5 s

to find:

velocity = ?

formula used:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

solution:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

v = 0 + (0.6 × 4.5)

v = 2.7 m/s

the minimum constant speed at which she can catch the train is 2.7 m/s