question_answer

  Define electric circuit. Draw symbols for (a) bulb (b) battery (c) close plug key (d) ammeter and connect them to form a circuit. Or (a) The flow of current in a circular wire creates a magnetic field at its centre. How can existence of this field be detected? State the rule which helps to predict the direction of magnetic field. (b) Represent uniform magnetic field and non-uniform magnetic field using a diagram. What does the density of field lines in a region indicate?

Answer:

  A closed conducting path through which electric current flows is called circuit.                                                    (1) Symbols (a) Bulb                                (b) Battery (c) Close plug                     (d) Ammeter key                                                                                                                                                                                         Circuit                                                                                                                                                                                 (2) Or The existence of this field can be detected by using a magnetic compass needle. The direction of magnetic field is predicted by using Maxwell's right-hand thumb rule.                                                                      It states that, if you hold a current-carrying conductor in right-hand, such that, the thumb points in the direction of electric current, then the direction in which fingers encircle, gives the direction of magnetic field.                                                                                                                                                                                                    The uniform and non-uniform magnetic fields are shown in the diagram below                                                 (1) Denser the field lines, stronger is the magnetic field in that region.                                                                          (1)