What is the role of saliva in the digest | Class 10 Science Chapter Life Processes, Life Processes 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?

Name the correct substrates for the following enzymes
(a) Trypsin              (b) Amylase
(c) Pepsin               (d) Lipase

Make a list of conventional and non-conventional sources of energy. Give a brief description of harnessing one non-conventional source of energy.

Suggest a few measures for controlling carbon dioxide levels in the atmosphere.

Why are crop fields known as artificial ecosystems?

Explain the terms analogous and homologous organs with examples.

Differentiate between biodegradable and non-biodegradable substances. Cite examples.

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

How do Mendel’s experiments show that traits may be dominant or recessive?

Make a diagram to show how hypermetropia is corrected. The near point of a hypermetropic eye is 1 m. What is the power of the lens required to correct this defect? Assume that the near point of the normal eye is 25 cm.

Why is sodium kept immersed in kerosene oil?