CBSE Physics Magnetic Effects of Current Expected Questions : Unit IV
Short Answer Type Question
Q. 1. Why is that a moving charge is deflected from its path when a magnetic field is applied on it ?
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Q. 2. A beam of electrons is moving parallel to a beam of protons in the same direction with equal speed. Will they attract or repel each other ?
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Q. 3. Current loop does not tend to rotate when its plane is ┴ to the direction of magnetic field. Why?
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Q. 4. State Flemings’ left hand rule.
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Q. 5. State Ampere’s circuital law.
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Q. 6. Define tesla. In what other ways can it be written ?
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Q. 7. What is Hall effect ?
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Q. 8. Two parallel wires carrying currents in the same direction attract each other, while two beams of electrons travelling in the same direction repel each other. Why ?
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Q. 9. A galvanometer has a reistance of 100 ohm. A resistance of 1 Q is connected across its terminals. What part of the total current flows through the galvanometer ? Draw the diagram.
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Q. 10. How can a voltmeter of resistance 200 ohm and measuring 10 V be used to measure a current of 5 A ?
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Q. 11. A point charge q is moving with speed v perpendicular to magnetic field B as shown in the figure. Explain what should be the magnitude and direction of the applied electric field so that the net force acting on the eharge is zero.
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Q. 12. Copper has 8 X 1028 conduction electrons per cubic metre. A copper wire 1 m long and area cross-section 8 X 10-6m2 carrying a current and lying at right angle to a magnetic field of strength 5 X 10-3 T experiences a force of 8 X 10-2 N. Calculate the drift velocity of free electrons in the wire.
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Q. 13. A cyclotron’s oscillator frequency is 10 MHz. What should be the operating magnetic field for accelerating protons ? If the radius of its dee’s is 60 cm, what is K.E. of protons beam produced by acceleration ? Express answer in MeV.
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Q. 14. An electron is projected with a velocity of 105 m s-1 at right angles to the magnetic field of 0.019 G. Calculate the radius of the circle described by the electron.
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Q. 15 (a) A d.c. supply of 120V is connected to a large resistance X. A voltmeter of resistance 10 k Q placed in series in the circuit reads 4V. What is the value of X ?
(b) What do you think is the purpose of using a voltmeter, instead of an ammeter, to determine the large resistance X ?
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