The impulse response of an R-L circuit is a

1. rising exponential function
2. decaying exponential function
3. step function
4. parabolic function

Since I (s) =	V (s)
	Z (s)

V (t) = δ (t)
V (s)= 1

so, I (s) =	1
	R + Ls

L (t) =		1		e–^{(R / L) x t}
		L

(which in a decaying exponential function)