Answer:
14.52 minutes
<u>OR</u>
14 minutes and 31 seconds
Explanation:
Let's first start by mentioning the specific heat of air at constant volume. We consider constant volume and NOT constant pressure because the volume of the room remains constant while pressure may vary.
Specific heat at constant volume at 27°C = 0.718 kJ/kg*K
Initial temperature of room (in kelvin) = 283.15 K
Final temperature (required) of room = 293.15 K
Mass of air in room= volume * density= (4 * 5 * 7) * (1.204 kg/m3) = 168.56kg
Heat required at constant volume: 0.718 * (change in temp) * (mass of air)
Heat required = 0.718 * (293.15 - 283.15) * (168.56) = 1,210.26 kJ
Time taken for temperature rise: heat required / (rate of heat change)
Where rate of heat change = 10000 - 5000 = 5000 kJ/hr
Time taken = 1210.26 / 5000 = 0.24205 hours
Converted to minutes = 0.24205 * 60 = 14.52 minutes
Answer:
Made of Silicon.
Explanation:
A diode is a semiconductor device use in mostly electronic appliances. It is two terminals device consisting of a P-N junction formed either in Germanium or silicon crystal.
Diode can be forward biased or reverse biased.
When a diode is forward biased and the applied voltage is increased from zero, hardly any current flows through the device in the beginning.
It is so because the external voltage is being opposed by the internal barrier voltage whose value is 0.7v for silicon and 0.3v for germanium.
If you measure 0.7 V across a diode, the diode is probably therefore made of Silicon.
If it is. DC, direct current reverse the polarity of power leads on the motor.
If it is a 3 phase ac alternating current, reverse any of the two of three leads.
Disconnect power before attempting.
Answer:
The company found the cost of the required photovoltaic cells too expensive.
Explanation:
Solar energy can be used as an alternative source of supply for fuel. Solar energy is a renewable source of energy, that is it keeps on replenishing every day. Also solar energy does not require a lot of maintenance.
The cost required is starting a solar system is very high because one needs to buy solar panel, photovoltaic cells for batteries, inverters and so on.
From the question, the company decided against solar energy for the time being. This means that probably in the future they might consider it. Therefore it is as a result of the economic situation of the company that they have not set up a solar system because the cost of the required photovoltaic cells too expensive.
