How much energy, in kJ, does a 75 Watt light bulb use if turned on for one second?

Question

1. How much energy, in kJ, does a 75 Watt light bulb use if turned on for one second?
2. how much energy, in kJ, does a 50 Watt light bulb use if turned on for one hour?
3. what is the energy consumed when using 5W for 2 hours?
4. suppose a hair dryer uses 20 kJ of energy. How many kWh is this?
5. suppose a TV uses 200 J of energy. How many BTUs is this?
6. sandy went to the gym and burned 500kcal of energy. How many joules is this?

Answer 1

1. How much energy, in kJ, does a 75 Watt light bulb use if turned on for one second?
2. how much energy, in kJ, does a 50 Watt light bulb use if turned on for one hour?
3. what is the energy consumed when using 5W for 2 hours?
4. suppose a hair dryer uses 20 kJ of energy. How many kWh is this?
5. suppose a TV uses 200 J of energy. How many BTUs is this?
6. sandy went to the gym and burned 500kcal of energy. How many joules is this?

1. 75 Watt = 75 J/s = 75/1000 KJs =75*60*60/1000 KJ/hr = 270 J in one hour
2. 50 Watt = 50 J/s = 50/1000 KJ/s = 50 *60*60 * /1000 J in one hour = 180 KJ/ hour , So in 2 hors =360 KJ For other answers ,Now use ,1BTU = 1055.06 J , 1 Kcal = 4184 J

and 1KWHr = 3600 KJ