Question

name the physical quantity which is i) same and ii) different in the following cases where three bulbs of :a) same wattage are connected in series....... b) same wattage are connected in parallel............ c) different wattage are connected in series......... d) different wattage are connected in parallel

Answer 1

Well... In the question nothing is specified about voltage  ratings of bulb are same or different.I assume it as they are same .
So the answer would be :
a)Physical quantity which remains same  when some wattage are connected in series :
--->Same wattage , so same voltage then same resistance
--> Same voltage drop means same voltage drop across the bulbs.hence  current, potential drop, resistance and luminosity of bulb remains same 
Different ---none

b)Same wattage are connected in parallel:Answer would be : same potential drop, current  and resistance.Different
 --none

c) Different wattage are connected in series:
If wattage is different with same voltage rating then resistance will be different then potential drop also differs.Only electric current remains same.

d)Different wattage are connected in parallel:
If wattage is different with same voltage then the resistance are different too . Current also differs .Luminosity also differs.

Answer 2

Well... In the question nothing is specified about voltage  ratings of bulb are same or different.I assume it as they are same .

So the answer would be :

a)Physical quantity which remains same  when some wattage are connected in series :

--->Same wattage , so same voltage then same resistance

--> Same voltage drop means same voltage drop across the bulbs.hence  current, potential drop, resistance and luminosity of bulb remains same 

Different ---none

b)Same wattage are connected in parallel:Answer would be : same potential drop, current  and resistance.Different

 --none

c) Different wattage are connected in series:

If wattage is different with same voltage rating then resistance will be different then potential drop also differs.Only electric current remains same.

d)Different wattage are connected in parallel:

If wattage is different with same voltage then the resistance are different too . Current also differs .Luminosity also differs.