Write one example for each of decomposition reaction carried out
with help of
(i) Electricity (ii) Heat (iii) Light

Dear student , 
The types of three different  examples of decomposition reactions are as follows :
1. Thermal decomposition:    CaCO₃  $\stackrel{Heat}{\to }$   CaO (s)   + CO₂(g) 
2. Electrical decomposition:  2 H₂O  $\stackrel{Electricity}{\to }$  2 H₂(g)        +     O₂(g)
                                                                              At cathode      At anode
3. Photochemical decomposition :  2 AgBr  $\stackrel{Sunlight}{\to }$   Ag (s)  + Br₂(g)
Regards