The intensity of an image of an object formed by a convex lens is i.
the intensity of this image can be made i÷4 by
(1) decreasing the size of the object.
(2) decreasing the sidtance of the object from the lens.
(3) covering one half of the lens with a black paper.
(4) covering three fourth of the lens with a black paper.

In the circuit, the switch s has been open for a long time and r = 125 kohm. it is then suddenly closed. (a) determine the time constant before the switch is closed. s (b) determine the time constant after the switch is closed. _ s (c) let the switch be closed at t = 0. find the current in the switch as a function of time. (use t for time. express your answer in milliamps and seconds.) i(t) =_