The power rating of a clock is 10 w, and the cost of electrical energy is $0.15 per kilowatt-hour. rounded to the nearest cent, how much does it cost to run the clock for one whole week?

$0.252

Explanation:

The power rating of an appliance suggests the amount of energy consumed per unit time.

The power rating of clock is given as 10 W.

It runs for 1 week. 1 week = 7 days = 7 ×24 hours = 168 hours

Consumption of electrical energy in one week would be = 1680 Watt-hour = 1.68 kW-hr

It is given that the cost of electrical energy is $0.15 per kW-hr

Thus, the total cost to run the clock would be:

$0.15 per kW-hr × 1.68 kW-hr = $0.252

the bal will not change its velocity.

speed of light in vacuum is 300,000 km/s

speed of light in other mediums is given by the expression v = c/n, where c is the speed of light in vacuum and n is the refractive index of medium.

for the first medium v = 200,000 km/s

  so, refractive index of medium = 300000/200000 = 1.5

    1.5 refractive index is usually for glass. so first medium is glass.

for the second medium v = 250,00 km/s

so, refractive index of medium = 300000/250000 = 1.2

    1.2 refractive index is usually for water. so second medium is water.

for the third medium v = 0 km/s

so, refractive index of medium = 300000/0 = ∞

    ∞ refractive index is usually for opaque mediums. so third medium is opaque medium.