A copper wire has diameter 0.5 mm and re | Class 10 Science Chapter Electricity, Electricity 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?

Compare and contrast the arrangement of elements in Mendeléev’s Periodic Table and the Modern Periodic Table.

Give the pair of contrasting traits of the following characters in pea plant and mention which is dominant and recessive
(i) yellow seed         (ii) round seed

Differentiate between inherited and acquired characters. Give one example for each type.

Why is small intestine in herbivores longer than in carnivores?

How is the amount of urine produced regulated?

Why is blood circulation in human heart called double circulation?

(a) Locate and name the water reservoirs in Figures16.1 (a) and (b).
(b) Which has an advantage over the other and why?

How does fertilisation take place? Fertilisation occurs once in a month. Comment.

Why does absorption of digested food occur mainly in the small intestine?

Compute the heat generated while transferring 96000 coulomb of charge in one hour through a potential difference of 50 V.