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प्रश्न
What is an artificial magnet? State two reasons why do we need artificial magnets .
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उत्तर
An artificial magnet is a magnetized piece of iron (or other magnetic material). Artificial magnets are required because natural magnets have odd and irregular shape and they are not magnetically very strong. Artificial magnets can be given desired shape and made very strong.
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संबंधित प्रश्न
Which of the following statements is incorrect regarding magnetic field lines?
(a) The direction of magnetic field at a point is taken to be the direction in which the north pole a magnetic compass needle points.
(b) Magnetic field lines are closed curves.
(c) If magnetic field lines are parallel and equidistant, they represent zero field strength.
(d) Relative strength of magnetic field is shown by the degree of closeness of the field lines.
A magnetic field exerts no force on:
an electrical charge moving perpendicular to its direction
an unmagnetised iron bar
a stationary electric charge
a magnet
Figure. shows a bar magnet placed on the table top with its north pole pointing towards south. The arrow shows the north-south direction. There are no other magnets or magnetic materials nearby.
Insert two magnetic field lines on either side of the magnet using arrow head to show the direction of each field line.
A charge of 5000 C flows through an electric circuit in 2 hours and 30 minutes. Calculate the magnitude of current in a circuit.
A battery can supply a charge of 25 × 104 C. If the current is drawn from battery at the rate of 2.5 A, calculate the time in which battery will discharge completely.
Define the agonic line.
A circular loop placed in a plane perpendicular to the plane of paper carries a current when the key is ON. The current as seen from points A and B (in the plane of paper and on the axis of the coil) is anti clockwise and clockwise respectively. The magnetic field lines point from B to A. The N-pole of the resultant magnet is on the face close to
A student fixes a white sheet of paper on a drawing board. He places a bar magnet in the centre and sprinkles some iron filings uniformly around the bar magnet. Then he taps gently and observes that iron filings arrange themselves in a certain pattern.
- Why do iron filings arrange themselves in a particular pattern?
- Which physical quantity is indicated by the pattern of field lines around the bar magnet?
- State any two properties of magnetic field lines.
Name the poles P, Q, Rand S of the magnets in the following figures 'a' and 'b':
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| Figure 'a' | Figure 'b' |
State the inference drawn about the direction of the magnetic field lines on the basis of the following diagrams.
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| Figure 'a' | Figure 'b' |
