Tag: energy management
Questions Related to energy management
Of the following, flames produced by a candle is
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Blue flame
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Non-luminous flame
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Light giving flame
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Yellow luminous flame
The energy which directly changes into electric energy in a solar cell is :
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heat energy only
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light energy only
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heat and light energy
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none of these
A solar cell gathers sunlight. It is the light energy which is converted into electrical energy.
The device which directly converts solar energy into electric energy is called
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solar cooker
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solar furnace
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solar cell
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none of these
A solar cell takes solar energy directly from the sunlight and converts it into electrical energy.
In a mechanically isolated system, which interaction is allowed?
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Mass flow
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Work
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Heat flow
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None of these
A mechanically isolated system is that , which cannot do work on environment and there is no exchange of mass between system and environment but exchange of heat is allowed between system and environment .
In a steady state process, which of the following quantity remains constant throughout the process
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Enthalpy
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Entropy
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Temperature and heat both
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Internal energy
A steady state is a state which remains the same over given time period. In heat transfer problems if there is specific rate of heat transfer through medium (for conduction or convection) and if it remains constant at any time then it is said to have steady state heat transfer. In steady state, there may be different temperatures in body at different locations but the temperature at any given point will remain constant. If the temperature at all locations is same then it is uniform.
Which of the following is/are macroscopic variables:
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Volume
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Temperature
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Pressure
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All of the above
Macroscopic variable is a measurable quantity used to describe the complete state of the system. The state of a macroscopic system in equilibrium can be described in terms of measurable properties as temperature, pressure, and volume, which are also known as thermodynamic variables.
Which of the following are macroscopic properties?
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texture
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phase
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viscosity
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all of the above
$Answer:-$ D
Macroscopic properties are qualities that can be seen by the naked eye, and some are relative to the conditions under which a material or element is observed. The three most basic examples of macroscopic properties are color, shape and size.
Other examples of macroscopic properties include texture, phase (solid, liquid or gas), viscosity (if any) and density relative to surroundings (such as oil on water). The properties of an element or material tend to change, even if only slightly, as the conditions change. Examples of changing conditions include how metals tend to glow red when heated to extreme temperatures, how the viscosity of honey decreases with temperature or how the volume of $H _2O$ increases slightly when it freezes.
The temperature of the biodigester is kept around $35^{\circ}C$, so as to sustain the fermentation of animal during slurry.
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True
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False
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Ambiguous
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Data insufficient
Answer is A.
This is a complex process by which organic matter is decomposed by anaerobic bacteria. The decomposition process produces a gaseous byproduct often called biogas, which consists primarily of methane, carbon dioxide, and hydrogen sulfide. It occurs in nature and can be used to produce biogas from biomass in an anaerobic digestor.
To optimize the digestion process, the biodigester must be kept at a consistent temperature, as rapid changes will upset bacterial activity. In most areas of the United States, digestion vessels require some level of insulation and/or heating. Some installations circulate the coolant from their biogas-powered engines in or around the digester to keep it warm, while others burn part of the biogas to heat the digester. In a properly designed system, heating generally results in an increase in biogas production during colder periods.
Hence, the statement is true.
The ................ animal dung left after the production of biogas is an excellent manure.
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spent
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coal
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methane
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pesticides
The dried manure left after the biogas process is even richer than ordinary muck and makes a fantastic organic fertilizer.
Hence, The spent animal dung left after the production of biogas is an excellent manure.
When solar dryer is placed in a sunlight, then :
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Air inside it is cooled
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Air inside it is heated
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Air remain as such
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None of these
When solar dryer is placed in sunlight then it convert solar energy into heat energy and heat the air inside the solar dryer to a constant temperature.
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