What are the disadvantage of solar energy
(a) A large surface area is required collect the solar
(b) Daily average of solar energy varies from 4 to 7 kwh/m2
(c) Highly hazardous toxic material is used in the manufacturing of solar device.
(d) All of the above are disadvantages.

Which of the following organism produces biogas from cow drug sherry in the biogas plant?
(a) aerobic bectria
(b) anaerobic bectria
(c) prolozoa
(d) fungi

Biogas is a better fuel than animal dung cake because
(a) biogas has lower calorific value.
(b) animal dung cake has high calorific value
(c) biogas bums smoke and leaves no residue
(d) biogas is used as a fuel for cooking only wheareas dung cake can be used for cooking, illuminant the lanterns.

Select the important factor for the site selection of a thermal power plant.
(a) Distance from the populated area
(b) Availability of fuel
(c) Availability’ of water
(d) Cost of plant

Which of the following problem is associated with a burning of coal?
(а) Carbon-dioxide emission
(b) acid rain
(c) ash with toxic metal supurity
(d) all of these.

Dead organisms are transformed into petroleum and natural gas in
(a) presence of air
(b) absence of air
(c) presence of sunlight
(d) none of the above