Fresh milk has a pH of 6. How do you thi | 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?

Suggest any four activities in daily life which are eco-friendly.

How can we explain the reddish appearance of sun at sunrise or sunset? Why does it not appear red at noon?

Why does the cord of an electric heater not glow while the heating element does?

The brain is responsible for

(a) thinking.
(b) regulating the heart beat.
(c) balancing the body.
(d) all of the above.

Give any two ways in which non-biodegradable substances would affect the environment.

Explain the meanings of malleable and ductile.

Why are coils of electric toasters and electric irons made of an alloy rather than a pure metal?

What are alloys?

What will happen if intake of iodine in our diet is low?

Draw ray diagrams each showing (i) myopic eye and (ii) hypermetropic eye.