What is (a) the highest, (b) the lowest | 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?

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

If a plant is releasing carbon dioxide and taking in oxygen during the day, does it mean that there is no photosynthesis occurring? Justify your answer.

Suggest suitable mechanism (s) for waste management in fertiliser industries.

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

How are water and minerals transported in plants?

What will happen if we kill all the organisms in one trophic level?

What are alloys?

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

Why does micelle formation take place when soap is added to water? Will a micelle be formed in other solvents such as ethanol also?

In tobacco plant, the male gametes have twenty four chromosomes.
What is the number of chromosomes in the female gamete?
What is the number of chromosomes in the zygote?