The current in a 120-V reading lamp is 2.6 A. If the cost of electrical energy is $0.075 per kilowatt-hour, how much does it cost to operate the light for an hour

P(power) = I V = 2.6 * 120 = 312 J/s

P = 312 J/s / 1000 J/kw ]= .312 kw/sec

E = P * t = .312 kw    energy used in 1 sec by bulb

To use .312 kw for an hour costs $.075

So .312 * .075 = .0234 $ = 2.34 cents      each hour

grav force prop 1/r squared 2r all squared is 4rsquared 1/4rsquared quartered

find the surface area of the sphere to the nearest square unit. use a calculator.

a. 254 in.2

b. 64 in.2

c. 127 in.2

d. 1,018 in.2