A solution reacts with crushed egg-shell | Class 10 Science Chapter Acids, Bases and Salts, Acids, Bases and Salts 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?

Explain the terms analogous and homologous organs with examples.

The refractive index of diamond is 2.42. What is the meaning of this statement?

How many 176 Ω resistors (in parallel) are required to carry 5 A on a 220 V line?

Study the following cross and showing self pollination in F₁, fill in the blank and answer the question that follows

Parents            RRYY                     x                rryy
                        Round, yellow                          wrinkled, green
   F₁ —             Rr Yy                      x                ?
                        Round, yellow

State the principle of an electric generator.

Oil and fat containing food items are flushed with nitrogen. Why?

Give an example of a plant hormone that promotes growth.

How are water and minerals transported in plants?

In the context of conservation of natural resources, explain the terms reduce, recycle and reuse. From among the materials that we use in daily life, identify two materials for each category.

How are the alveoli designed to maximise the exchange of gases?