Answer:
See the answers below.
Explanation:
We will solve this problem by calculating each part separately.
A 500 W hair dyer is used to dry hair for 6 minutes a day for 3 days.
Energy can be calculated by multiplying the value of the power of the equipment by the amount of time of use.
![500 [W]*[\frac{6min}{1day} ]*[\frac{1day}{24hr} ]*[\frac{1hr}{60min} ]=2.083 [W]](https://tex.z-dn.net/?f=500%20%5BW%5D%2A%5B%5Cfrac%7B6min%7D%7B1day%7D%20%5D%2A%5B%5Cfrac%7B1day%7D%7B24hr%7D%20%5D%2A%5B%5Cfrac%7B1hr%7D%7B60min%7D%20%5D%3D2.083%20%5BW%5D)
The cots of electricity is 5.6 cents per kWh. How much would it cost to operate the laptop for 24 hours a day for one week?
We know that the power of the latop is 75 [W], then we can calculate the cost, multiplying the value of the power by the value of the cost by the time of use of the computer.
![0.075[kW]*5.6[\frac{cents}{kw*h}}]*[\frac{24hr}{1day}]*[1week]*[\frac{7days}{1week} ]=70.56 [cents]](https://tex.z-dn.net/?f=0.075%5BkW%5D%2A5.6%5B%5Cfrac%7Bcents%7D%7Bkw%2Ah%7D%7D%5D%2A%5B%5Cfrac%7B24hr%7D%7B1day%7D%5D%2A%5B1week%5D%2A%5B%5Cfrac%7B7days%7D%7B1week%7D%20%5D%3D70.56%20%5Bcents%5D)
A toaster oven is 85% efficient. It uses 1200 J of energy. How much thermal energy is it producing?
Efficiency is defined as the relationship between the energy obtained on the energy delivered. Almost always the energy delivered is greater than the energy obtained (first law of thermodynamics).
Therefore.
![Effic = E_{obtained}/E_{delivered}\\0.85=E_{obtained}/1200\\E_{obtained}=1020[J]](https://tex.z-dn.net/?f=Effic%20%3D%20E_%7Bobtained%7D%2FE_%7Bdelivered%7D%5C%5C0.85%3DE_%7Bobtained%7D%2F1200%5C%5CE_%7Bobtained%7D%3D1020%5BJ%5D)
The exact magnification of the objects is calculated by dividing the cinema. We calculate it by diving the erect image size by the object size. From the given above, we find the exact magnification by dividing 5.0 cm by 1.0 cm. Thus, the answer would be 5.
20 electrons and 2 valence electrons
Answer: 3.7×10¹²watts
Explanation:
Radiation is one of the mode of heat transfer and modes differs from each other based on their medium of heat transfer. Radiation is a process of transferring heat energy from one point to another without heating the intervening medium (no material medium is required).
According to Stefan's law of radiation, the rate of emission of radiant energy is directly proportional to the fourth power of its absolute temperature.
Mathematically, R = eAT⁴
e is constant of proportionality called emissivity. Emissivity varies depending on the type of body being considered.
For the question, we are considering black body and emissivity of black body is 1 being a perfect body.
A is the area of the body
T is the absolute temperature
e = 1
A = 0.5cm²
T = 1650°C
Rate of radiation = 1×0.5×1650⁴
= 3.7×10¹²watts.
The hole will therefore radiate 3.7×10¹²watts
Answer:
Mechanical waves require a medium to transfer their energy.
What are examples of mechanical waves?
Explanation:
Mechanical waves require a medium to transfer their energy.
What are examples of mechanical waves?
