Answer: C

Explanation:

Conventional energy sources exist in limited quantities in nature and are naturally produced at a slow rate. For example, fossil fuels are formed from decaying plants and animals over millions of years. Hence, statement 1 is correct.

Fossil fuels, such as coal, oil, petroleum, and natural gas, are some examples of traditional energy sources. All these fuels are carbon based and when they are burnt, energy is released. Hence, statement 2 is correct.

Answer: C

Explanation:

Dry cell, a primary or secondary cell in which the flow of electrolytes is prevented in some way. It is a type of electric battery commonly used in portable and home electronic devices. The dry cell is based on the Leclanche cell and consists of a low moisture stable electrolyte in paste form. Hence, statement 1 is correct.

These electrolytes clog the electrochemical cells and prevent them from flowing freely. Because of this, dry cells are quite portable. The dry cell is made of a circular cylinder of Zn metal which acts as an anode. There is a graphite rod in the middle of this cell which acts as a cathode. To make this cell insulated from all sides, a cover of thick paper is applied. Hence, statement 2 is correct.

Answer: C

Explanation:

Coal Bed Methane (CBM) is also called 'Coal Seam Gas' (CSG-Coal Seam Gas). Coal bed methane is found at great depth in coal deposits, that is, it is present in the coal bed located at great depth. Hence, statement 1 is correct.

In recent decades it has become an important source of energy in the US, Canada and other countries. Australia has abundant reserves of it, where it is known as coal seam gas. It is also called 'Sweet Gas', because it lacks hydrogen sulphide. Hence, statement 2 is correct.

The presence of this gas occurs in underground coal mines, where it poses very serious safety risks. Coal bed methane is completely different from a typical sandstone or other conventional gas reservoir. In fact, methane remains stored within the coal through the process of adsorption. It is produced by non-conventional means and hence when it is sold or used like conventional natural gas, its production is completely different. Hence, statement 3 is correct.

Answer: B

Explanation:

Algae biofuel is an alternative to energy-rich oils. It is also called algae fuel or algae oil. When it is made from seaweed (macroalgae), it is known as seaweed fuel or seaweed oil. Generally two types of algae are used to produce biofuel.

Macro Algal- A large amount of biofuel can be obtained from these, but their cultivation is quite expensive.

Micro Algal – The amount of biofuel obtained from these is less but their cultivation is quite cheap and easy.

Here, both Statement-I and Statement-II are correct but Statement-II is not the correct explanation of Statement-I. Hence, option (b) is correct.

Answer: C

Explanation:

Organic waste is capable of producing methane in landfill gas. Methane increases global warming 21 times more than CO₂. However, if methane is captured and burned, the greenhouse effect is greatly reduced. Methane can be collected by vacuum through pipes immersed in a landfill. After removing impurities, the landfill gas is compressed and can be used to generate electricity through a turbine. Apart from this, methane gas can be used to make steam from water for industrial purposes and as natural gas for domestic use. Hence, statements 1 and 2 both are correct.