Question for Zener Diode

Hi All,

I have some querries regarding the Zener diode. In case a Zener diode specification is Vz = 5.2V and Pzmax = 260mW and Rz = 0.
a)What is the maximum allowable current Iz when the Zener diode is acting as regulator?
b) If a single-loop circuit consists of an ideal 15-VDC source Vs, a variable resistor R and the described Zener diode, find the range of values of R for which Zener diode remains in constant reverse breakdown with no danger of failure.

My solution for a) is 50mA
b) R range is >= 196 Ohm since the VDC source is ideal

For Part a) I quite sure that the answer is correct however for Part b) Please help to check whether correct or not?

Need all your kind help.

Thanks a lot,

Best Regards,
Gilbert

You are correct.

Thanks Hayato..