Science
(a) State the relationship between the resistance R of a wire to its length l and cross sectional area A. Use the mathematical symbols to arrive at the final formula.
(b) Using the formula define the resistivity of a material.
Related Questions
(a) What is the fundamental difference between hypermetropia and myopia in terms of the optical experience of a person?
(b) The diagram below shows a special case of an eye defect.
(i) What is the defect that is shown in the figure?
(ii) State one cause for such a defect?
(iii) Explain with reason if a concave lens can be used to correct the defect.
(a) What is the fundamental difference between hypermetropia and myopia in terms of the optical experience of a person?
(b) What are the causes of myopia in the human eye?
Mona was doing an experiment with a magnetic compass and a straight current-carrying wire. She observed that as she moved the compass away from the current-carrying wire, the deflection of the compass needle reduced.
(a) Explain why the deflection of the compass needle reduced as Mona moved away the compass needle from the current carrying wire.
(b) Mention one thing that could have changed in the circuit of the wire that could increase the deflection of the needle.
(c) Explain with reason what will be the direction of the magnetic field associated with the wire for the case described by the above figure.
(a) Explain why the deflection of the compass needle reduced as Mona moved away the compass needle from the current carrying wire.
(b) Mention one thing that could have changed in the circuit of the wire that could increase the deflection of the needle.
(c) Explain with reason how the direction of the magnetic field associated with the wire changes if the polarity of battery reversed.