How has the traditional use of wind and | Class 10 Science Chapter Sources of Energy, Sources of Energy NCERT Solutions

When a 12 V battery is connected across an unknown resistor, there is a current of 2.5 mA in the circuit. Find the value of the resistance of the resistor.

Outline a project which aims to find the dominant coat colour in dogs.

Draw the structure for the following compounds.                

       (i)    Ethanoic acid             (ii)   Bromopentane*
       (iii)  Butanone                   (iv)   Hexanal.

*Are structural isomers possible for bromopentane?

A hot plate of an electric oven connected to a 220 V line has two resistance coils A and B, each of 24 Ω resistance, which may be used separately, in series, or in parallel. What are the currents in the three cases?

How is the sex of the child determined in human beings?

(a)  What property do all elements in the same column of the Periodic Table as boron have in common?
(b)  What property do all elements in the same column of the Periodic Table as fluorine have in common?

Calculate the number of electrons constituting one coulomb of charge.

A man with blood group A marries a woman with blood group O and their daughter has blood group O. Is this information enough to tell you which of the traits – blood group A or O – is dominant? Why or why not?

What is an homologous series? Explain with an example.

Why is variation beneficial to the species but not necessarily for the individual?

What is the function of an earth wire? Why is it necessary to earth metallic appliances?

What is common for cuscuta, ticks and leeches?

Suggest a few useful ways of utilising waste water.

Metallic oxides of zinc, magnesium and copper were heated with the following metals.

In which cases will you find displacement reactions taking place?

Label the parts of a neuron in Figure 7.5.

Write equations for the reactions of

   (i) iron with steam
   (ii) calcium and potassium with water.

What are the environmental consequences of using fossil fuels?
Suggest the steps to minimise the pollution caused by various sources of energy including non-conventional sources of energy.

What happens at the synapse between two neurons?

What are the environmental consequences of the increasing demand for energy? What steps would you suggest to reduce energy consumption?

A student has difficulty reading the blackboard while sitting in the last row. What could be the defect the child is suffering from? How can it be corrected?