Final answer:
A 60 W bulb uses 60 kWh of electricity in a day.
Step-by-step explanation:
A 60 W bulb uses 60 joules of electricity per second (since power is the rate of energy consumption and 1 joule per second is equal to 1 watt). To find out how many kilowatt-hours (kWh) it uses in a day, we need to convert the time from seconds to hours. There are 3600 seconds in an hour, so there are 3600 seconds ÷ 60 seconds in a minute ÷ 60 minutes in an hour = 1 hour. Therefore, the bulb uses 60 kWh of electricity in a day.