The correct option (b) 200 V, 50 Hz
Explanation:
N1 = 500
N2 = 5000
V1 = 20V
For transformer, (V1/V2) = (N1/N2) hence
(20/V2) = [(500)/(5000)]
(20/V2) = (1/10)
V2 = 200V
The frequency at secondary will be same as that at primary.
Hence V2 = 200 V, 50Hz.