Power, P = VI
Where V is the voltage and I is the current.
P = V x (V/R)
= V2/R
V2 = PR
V = SQRT[PR]
= SQRT[30 x 60]
= SQRT[1800]
= 42.43 V
4. A 12.0 watt LED bulb produces the same illumination as a 75.0 watt incandescent bulb. If energy costs S 0.123 per kWh, how much money would you save by using the LED bulb for 14.0 hours every day for 30 days instead of using the incandescent bulb?
Which has greater resistance: a 75 watt bulb or a 100 watt bulb?Suppose you connect a 75 watt bulb across only 50 volts: will you still get 75 watts of power?Suppose you connect a 100 watt bulb and a 75 watt bulb in series and then connect the combination to a regular 110 volt line. Which bulb (if either) will burn brighter?(note that we are talking about the older incandescent bulbs here... the newer types are quite different.)
A 24-volt battery is hooked to four 25-watt light bulb in series. a. Draw a digram of this circuit b. Find the voltage across each light bulb c. Find the current in each light bulb d. Find the resistance in each light bulb
A 60 W bulb and a 100 W bulb are each rated at 120 V. Which light bulb has a larger resistance? a) the 60 watt bulb b) the 100 Watt bulb c) same resistance
Let X be the length of life of a 60-watt light bulb manufactured by a certain company. If a random sample of 25 units is tested until they burn out, yielding a sample mean of x = 1478 hours and s 2 x = 1296, compute a confidence 95 % -confidence interval for the mean and the variance.
(a) How much current flows in a 100 watt bulb when lit? Assume 120 volts and assume DC voltage. (b) What is the resistance of a 100 watt light bulb when lit? Assume 120 volts and a tungsten filament temperature of 1200° C when lit. (c) How much current flow in the bulb when it is first turned on and the temperature of the filament is 20° C? Use α-5.36 x 10-3 Co.1 for tungsten.
-Find the voltage and current equations of the following circuit: R1 R-2 Ohm R2 R-4 Ohm . R3 R-10 Ohnm
A box in a certain supply room contains four 40-watt light bulbs, five 60-watt bulbs, and six 75-watt bulbs. Suppose that three bulbs are randomly selected. a. What is the probability that exactly two of the selected bulbs are rated 75-watt? b. What is the probability that all three of the elected bulbs have the same rating? c. What is the probability that one bulb of each type is selected? d. What is the probability that at least two of...
A "120-watt" lightbulb uses an average power of 120 W when connected to an rms voltage of 120 V. What is the resistance of the lightbulb? What is the maximum current in the bulb? What is the maximum power used by the bulb at any given instant of time?
3. How many Joules of energy are used by a 4 Watt bulb burning for 2 hours? How much would it be in kWh? in kwhp. E t For haw many Joules )(2x 36 00) 2 E-6kwh