Question Discussion & Solution

The correct answer is Fossil fuels.

Key Points

Non-Renewable Resources Examples

• Fossil Fuel
• Coal
• Rare earth elements
• Petroleum products
• Uranium

Thus, Fossil fuels are a non-renewable source of energy.

Additional Information 

Types of Renewable Energy

Solar Energy:

• ​The radiant light and heat energy from the sun is harnessed with the use of solar collectors.
• These solar collectors are of various types such as photovoltaics, concentrator photovoltaics, solar heating, (CSP) concentrated solar power, artificial photosynthesis, and solar architecture.
• This collected solar energy is then used to provide light, heat, and different other forms of electricity.

Wind Energy:

• The energy we get from winds is known as wind energy.
• For this, windmills have been used for hundreds of years to pump out water from the ground. We use large tall wind turbines that allow winds to generate electricity.
• The natural airflow on the surface of the earth is used to run the wind turbines.
• The most preferred locations for these wind turbines to be installed are the areas which and strong and have constant airflows on offshore and sites that are at high altitudes.

Hydroelectricity:

• According to statistics, hydroelectricity generated around 16.6% of the global energy resources and constituted about 70% of all the renewable electricity.
• This energy is another alternative source of energy that is generated by the construction of dams and reservoirs on the flowing water, the kinetic energy from the flowing water is used to run the turbines which generate electricity.
• Tidal power converts the energy of tides and Wave power which captures the energy from the surface of the ocean waves for power generation.
• These two forms of hydropower also have huge potential in electric power generation

Geothermal Energy:

• It is the energy that is generated from the thermal energy which is stored in the earth.
• The heat energy is captured on sources such as hot springs and volcanoes and this heat is directly used by industries for heating the water and other purposes.

Bio-Energy:

• This type of energy is derived from biomass which is a type of biological material derived from living organisms and plant-derived materials which are called lignocellulosic biomass.
• Biomass can be directly used via combustion to produce heat and indirectly it can be used to convert to biofuels.
• Biomass can be converted to other usable forms of energy such as transportation fuels like ethanol, biodiesel, and methane gas.

The correct answer is Copper.

Key Points

• Conductor of electricity
  • In physics and electrical engineering, a conductor is an object or type of material that allows the flow of charge in one or more directions.
  • Materials made of metal are common electrical conductors. 
  • Copper is considered to be a conductor because it conducts the electron current or flow of electrons fairly easily. Most metals are considered to be good conductors of electrical current. Copper is just one of the more popular materials that are used for conductors. Hence, Option 4 is correct.
  • If you have to define the meaning of electrical conductors in the simplest way, they are materials that allow electricity to flow through them easily.
  • If we compare two types of material and the first one allows better flow of electricity through it, then that material is said to be a good conductor of electricity.
  • An electrical conductor allows the electric charges to easily flow through them. The property of conductors to conduct electricity is called conductivity.
  • Such materials offer less opposition or resistance to the flow of charges.
  • Conducting materials allow easy charge transfer because of the free movement of electrons through them.

Additional Information

• • Some examples of conductors of electricity are
    • Copper
    • Aluminum
    • Silver
    • Gold
    • Graphite
    • Platinum
    • Water
    • People

Concept:

Classes in java are the collection of objects which has some similar properties. A class in java contains fields, methods, constructors, blocks, interfaces.

Explanation:

Everything is associated with classes and objects. An object is an instance of the class which has some state and behavior.

An object class(java.lang.object) is the parent class of all the java classes.  It can be used when we do not know about the type of the object. By having the object as the super class , without knowing the type we can pass around objects using the object declaration.

The correct answer is Rice.

• Rice blast disease, caused by Magnaporthe oryzae (Ascomycota), occurs in about 80 countries on all continents where rice is grown, in both paddy fields and upland cultivation.
• The extent of damage caused depends on environmental factors, but worldwide it is one of the most devastating cereal diseases, resulting in losses of 10–30% of the global yield of rice.
• Other common diseases of the crop of rice are - Blight, Bacterial leaf streak, Brown spot, Sheath blight, False smut, etc.

Additional Information

• The biological agents that causing diseases to plants are known as pathogens. 
• Some of the viral diseases in plants are - bud blight (soyabeans), Curly tops (Beans, tomato, etc.), Mosaic leaf (Tomato, pea, potato,tobacco, etc.).
• Some of the bacterial diseases in plants are - Blights (vegetable crops), Bacterial wilts (Tobacco, potatoes, etc), Cankers (Woody plants), Leaf Spots, Soft Wrots, etc.
• Some of the fungal diseases in the plants are - Cankers, Ergot, Rusts, Root rots, Scabs, Smuts, etc.
   

Concept:

• Any battery (actually it may have one or more than one cell connected in series) or cell that we use as a source of electrical energy is a galvanic cell where the chemical energy of the redox reaction is converted into electrical energy. 
• In the primary batteries, the reaction occurs only once, and after use over some time battery becomes dead and cannot be reused again.
• The most familiar example of this type is the dry cell (known as Leclanche cell after its discoverer) which is used commonly in our transistors and clocks. 
• The cell consists of a zinc container that also acts as anode and the cathode is a carbon (graphite) rod surrounded by powdered manganese dioxide and carbon.
• The space between the electrodes is filled by a moist paste of ammonium chloride (NH4Cl) and zinc chloride (ZnCl2). 

Explanation:

• The cell consists of a zinc container that acts as the anode.
• The cathode is a carbon (graphite) rod surrounded by a cathodic material powder of manganese dioxide and carbon.

So, The positive pole of the dry cell is made up of C (carbon).