Assertion : Current versus potential difference (i-V) graph for a conductor at two different temperatures `T_(1)` and `T_(2)` is shown in figure. Hence `T_(1)gt T_(2)`.

Reason : Resistance of a conductor increases with rise in temperature.

Answer

`((a)/(2),(7a)/(10))`

Explanation

`x_(cm) = ((m xx 0) + (2m xx a) + (3m xx a) + (4m xx 0))/(m + 2m + 3m + 4m)= (a)/(2)`
`y_(cm) = ((m xx 0) + (2m xx 0)+ (3m xx a) + (4m xx a))/(m + 2m + 3m + 4m) =(7a)/(10)`