Question

a bulb of 40 watt is joined with 220 volt of AC current and bulb is used for 10 hrs per. day then the units of 30 days will be

Answer 1

for one day= no.of watts *no.of hours/1000. =40*10/1000 =0.4. for 30 days =30*0.4=12units will be consumed

Answer 2

Answer: (b) 12 units

Explanation:

Given: 40watt ,220v and 10hrs.

Find: units in 1 month.

Note:There will be no use of 220 v because this is permanent volt that comes in our house.

Now.,

Units=(40×10)/1000=4/10

Units in 30 days=4/10×30=12units

Hence, there will be 12units used in 30 days.