Tag: solar energy and its applications

Questions Related to solar energy and its applications

Which of the following is/are macroscopic variables:

physics energy management solar power plant production of electricity from solar energy solar equipment solar energy and its applications

  1. Volume

  2. Temperature

  3. Pressure

  4. All of the above

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Correct Option: D
Explanation:

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?

physics energy management solar power plant production of electricity from solar energy solar equipment solar energy and its applications

  1. texture

  2. phase

  3. viscosity

  4. all of the above

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Correct Option: D
Explanation:

$Answer:-$ 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.

physics energy management solar power plant production of electricity from solar energy solar energy and its applications

  1. True

  2. False

  3. Ambiguous

  4. Data insufficient

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Correct Option: A
Explanation:

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.

physics energy management solar power plant production of electricity from solar energy solar energy and its applications

  1. spent

  2. coal

  3. methane

  4. pesticides

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Correct Option: A
Explanation:

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 :

physics energy management solar power plant production of electricity from solar energy solar energy and its applications

  1. Air inside it is cooled

  2. Air inside it is heated

  3. Air remain as such

  4. None of these

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Correct Option: B
Explanation:

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.

State whether true or false :
In solar dryer, we can keep dried fruits for longer duration of time.

physics energy management solar power plant production of electricity from solar energy solar energy and its applications

  1. True

  2. False

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Correct Option: A
Explanation:

 Solar dryer is one of the oldest methods of preserving food for later use.  Foods can  be dried in the sun, in an oven or in a food dehydrator by using the right. So we can dried fruits for longer duration of time.

State whether true or false :
Solar dryer works on the principle of conversion of solar energy into heat energy.

physics energy management solar power plant production of electricity from solar energy solar energy and its applications

  1. True

  2. False

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Correct Option: A
Explanation:

The basic function of a solar dryer is to heat air to a constant temperature with solar energy hence Solar dryer works on the principle of conversion of solar energy into heat energy.

State whether true or false :
Solar dryer can be used in night also.

physics energy management solar power plant production of electricity from solar energy solar energy and its applications

  1. True

  2. False

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Correct Option: B
Explanation:

At night there is no sunlight to produce heat energy so we cannot use solar cookers in night.

State whether true or false :
The purpose of glass cover placed on solar dryer is to sustain the heat.

physics energy management solar power plant production of electricity from solar energy solar energy and its applications

  1. True

  2. False

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Correct Option: A

The purpose of black coloured box in a solar dryer is to :

physics energy management solar power plant production of electricity from solar energy solar energy and its applications

  1. Absorb more heat

  2. Absorb less heat

  3. Reflect light

  4. None of these

Show answer
Correct Option: A
Explanation:

We use the black coloured box to absorb more heat as black colour is the best absorber for heat among its all colours.