Class 10 Science - Chapter Magnetic effects of Electric Current NCERT Solutions | Choose the correct option. A rectangu

The magnetic field in a given region is uniform. Draw a diagram to represent it.

How does a solenoid behave like a magnet? Can you determine the north and south poles of a current–carrying solenoid with the help of a bar magnet? Explain.

Explain the underlying principle and working of an electric generator by drawing a labelled diagram. What is the function of brushes?

In Activity 13.7, how do we think the displacement of rod AB will be affected if (i) current in rod AB is increased; (ii) a stronger horse-shoe magnet is used; and (iii) length of the rod AB is increased?

A positively-charged particle (alpha-particle) projected towards west is deflected towards north by a magnetic field. The direction of magnetic field is

   (a) towards south                 (b) towards east
   (c) downward                       (d) upward

Consider a circular loop of wire lying in the plane of the table. Let the current pass through the loop clockwise. Apply the right-hand rule to find out the direction of the magnetic field inside and outside the loop.

Draw a labelled diagram of an electric motor. Explain its principle and working. What is the function of a split ring in an electric motor?

Draw magnetic field lines around a bar magnet.

State Fleming’s left-hand rule.

List the properties of magnetic field lines.

Did Döbereiner’s triads also exist in the columns of Newlands’ Octaves? Compare and find out.

What is a good source of energy?

Why is diffusion insufficient to meet the oxygen requirements of multi-cellular organisms like humans?

What are trophic levels? Give an example of a food chain and state the different trophic levels in it.

What changes can you make in your habits to become more environment-friendly?

What is the difference between a reflex action and walking?

What is the importance of DNA copying in reproduction?

If a trait A exists in 10% of a population of an asexually reproducing species and a trait B exists in 60% of the same population, which trait is likely to have arisen earlier?

Why should a magnesium ribbon be cleared before burning in air?

Define the principal focus of a concave mirror.

Draw the electron dot structures for

(a) ethanoic acid.
(b) H₂S.
(c) propanone.
(d) F₂.

Why are the small numbers of surviving tigers a cause of worry from the point of view of genetics?

What are the advantages of sexual reproduction over asexual reproduction?

Identify the substances that are oxidised and the substance that are reduced in the following reactions.

    (i)    4Na(s)   +   O₂(g)    →    2Na₂O(s)
    (ii)   CuO(s)   +   H₂(g)    →    Cu(s)   +   H₂O(l)

Why is sodium kept immersed in kerosene oil?

Explain the following.

(a) Why is the tungsten used almost exclusively for filament of electric lamps?
(b) Why are the conductors of electric heating devices, such as bread-toasters and electric irons, made of an alloy rather than a pure metal?
(c) Why is the series arrangement not used for domestic circuits?
(d) How does the resistance of a wire vary with its area of cross-section?
(e) Why are copper and aluminium wires usually employed for electricity transmission?

How do Mendel’s experiments show that traits are inherited independently?

What are the changes seen in girls at the time of puberty?

A concave lens of focal length 15 cm forms an image 10 cm from the lens. How far is the object placed from the lens? Draw the ray diagram.

Can you think of reasons why more complex organisms cannot give rise to new individuals through regeneration?