Why don’t two magnetic field lines | Class 10 Science Chapter Magnetic effects of Electric Current, Magnetic effects of Electric Current 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 far point and near point of the human eye with normal vision?

Will geographical isolation be a major factor in the speciation of a self-pollinating plant species? Why or why not?

Find out the source of water in your region/locality. Is water from this source available to all people living in that area?

What will happen if platelets were absent in the blood?

What were the criteria used by Mendeléev in creating his Periodic Table?

Why is diffusion insufficient to meet the oxygen requirements of multi-cellular organisms like humans?

What is a good fuel?

How does the electronic configuration of an atom relate to its position in the Modern Periodic Table?

The far point of a myopic person is 80 cm in front of the eye. What is the nature and power of the lens required to correct the problem?

In the Modern Periodic Table, calcium (atomic number 20) is surrounded by elements with atomic numbers 12, 19, 21 and 38. Which of these have physical and chemical properties resembling calcium?