When is the force experienced by a current–carrying conductor placed in a magnetic field largest?
When the direction of current is perpendicular to the direction of magnetic field. The force experienced by the current carrying conductor is maximum.
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.
List the properties of magnetic field lines.
State Fleming’s left-hand rule.
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.
Give a test that can be used to differentiate between saturated and unsaturated hydrocarbons.
If all the waste we generate is biodegradable, will this have no impact on the environment?
Plaster of Paris should be stored in a moisture-proof container. Explain why?
What advantage over an aquatic organism does a terrestrial organism have with regard to obtaining oxygen for respiration?
How are the alveoli designed to maximise the exchange of gases?
What are the problems caused by the non-biodegradable wastes that we generate?
What were the limitations of Döbereiner’s classification?
Why is damage to the ozone layer a cause for concern? What steps are being taken to limit this damage?
Why do stars twinkle?
How does phototropism occur in plants?