How does knowing the time constant of an RL or RC circuit help us decide the width of a practical pulse input that is short enough to provide a good approximation of an impulse

The place you get your hair cut has two nearly parallel mirrors 6.00 m apart. as you sit in the chair, your head is 2.00 m from the nearer mirror. looking toward this mirror, you first see your face and then, farther away, the back of your head. (the mirrors need to be slightly nonparallel for you to be able to see the back of your head, but you can treat them as parallel in this problem.) how far away does the back of your head appear to be?

Which of the following changes will result in a stronger electromagnet? a. using fewer coils of wire b. using a higher voltage c. using a shorter nail d. using a longer wire

Clothes dryer uses about 7 amps of current from a 240 volt line. how much power does it use?