An ac source of period t and maximum voltage v is connected to a single unknown ideal element that is either a resistor, and inductor, or a capacitor. at time t = 0 the voltage is zero. at time t = t/4 the current in the unknown element is equal to zero, and at time t = t/2 the current is i = -imax, where imax is the current amplitude. what is the unknown element?

This satisfy the above given condition so we can say that this capacitor.

Explanation:

Let's take one by one option and check whether is wrong or right

For inductor:

Given that at t=T/4 ,I=0 and we know that

So at T/4

I=0 A

At t=T/2

It means that this not a indutor.

For capacitor:

At T/4, I=0

At t=T/2

This satisfy the above given condition so we can say that this capacitor.

so easy. just google the electromagnetic waves and it’ll pop up.

you can cut your hand off if your not