How does phototropism occur in plants? | Class 10 Science Chapter Control and Coordination, Control and Coordination 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 various plant hormones. Also give their physiological effects on plant growth and development.

Why are the Arabari forests of Bengal known to be a good example of conserved forest?

The image formed by a concave mirror is observed to be virtual, erect and larger than the object. Where should be the position of the object?

(a) Between the principal focus and the centre of curvature
(b) At the centre of curvature
(c) Beyond the centre of curvature
(d) Between the pole of the mirror and its principal focus.

In the electrolytic refining of a metal M, what would you take as the anode, the cathode and the electrolyte?

Butanone is a four-carbon compound with the functional group

(a) carboxylic acid.
(b) aldehyde.
(c) ketone.
(d) alcohol.

Explain the structure and functioning of Human eye. How are we able to see nearby as well as distant objects?

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

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

Give an example of a double displacement reaction other than the one given in activity 1.10.

Compare and contrast nervous and hormonal mechanisms for control and coordination in animals.