MAGNETIC EFFECTS OF ELECTRIC CURRENT – 5 Mark Questions

Q1.  Explain with the help of a    labelled diagram, the distribution of magnetic field due to a  current through a  circular loop. Why is it that, if a current-carrying coil has n turns, the field produced at any point is n times as large as that produced by a single turn?

Q2.         (i)  Draw the magnetic field lines through and around a single loop of wire carrying electric current.

                 (ii)   State whether an α-particle will experience any force in a magnetic field, if (α-particles are positively charged particles).

(a)  It is placed in the field at rest.

(b)  It moves in the magnetic field parallel to field lines.

(c) It moves in the magnetic field perpendicular to field lines. Justify your answer in each case.

Q3. Explain, why electric power transmitted at high voltages and low currents to distant places?

Q4. (i) What is a solenoid?

        (ii) Draw the pattern of magnetic field formed around a current-carrying solenoid. Compare this field to that of a bar magnet.

       (iii) Explain an activity to show that a current-carrying conductor experiences a force when placed in a magnetic field.

Q5. (i)  A coil of insulated copper wire is connected to a galvanometer. What happens if a bar magnet is:

(a) Pushed into the coil?

(b) Withdrawn from inside the coil?

(c) Held stationary inside the coil?

Give reasons for your observation.

      (ii) Mention one more method of inducing current in a coil.

Q6. (i)  A stationary charge is placed in a magnetic field.  Will it experience a force? Give reason to justify your answer.

         (ii) On what factors does the direction of force experienced by a conductor when placed in a magnetic field depend?

         (iii) Under what conditions is the force experienced by a current-carrying conductor placed in a uniform magnetic field maximum?

        (iv) Name and state the rule which gives the direction of force experienced by a current carrying conductor placed in a magnetic field.

Q7. (a) Define electromagnetic induction.

         (b) Two coils P and S are wound over the same iron core. Coil P is connected to battery and key and the coil S is connected to galvanometer. Write your observations when:

(i)  Current in the coil P is started by closing the key.

(ii) Current continues to flow in coil P.

(iii)Current in coil P is stopped by removing the key.

Explain the reason for such observation.

Q8. (a) Draw a schematic labelled diagram of domestic electric circuit.

         (b) Why is it necessary to provide-

(i) A fuse in an electric circuit

(ii) An earth wire to electric application metallic body? Explain.

Q9. (i) Explain what is the difference between a direct current and an alternating current. Write one important advantage of using alternating current.

         (ii) An air conditioner of 2kW is used in an electric circuit having a fuse of 10A rating. If the potential difference of the supply is 220 V, will the fuse be able to withstand, when the air conditioner is switched on? Justify your answer.

Q10. (i) Explain two safety measures commonly used in electric circuits and appliances.

            (ii) An electron enters a magnetic field at right angles to it as shown in figure. What will be the direction of force acting on the electron? State the rule which gives direction of force on electron.

            (iii) If instead of electron, a neutron enters a field, what will be its direction of motion? Give reason for your answer.

Q11.  (i) How does the strength of magnetic field due to current carrying conductor depends upon the current flowing and distance from the conductor?

            (ii) α-particles are positively charged particles.  State whether an a-particle will experience any force in a magnetic field, if

(a) it is placed in field at rest.

(b) it moves in the magnetic field parallel to field lines.

(c) it moves in the magnetic field perpendicular to the field lines. Justify your answer in each case.

Q12. Explain with the help of a labelled diagram, the distribution of magnetic field due to current-carrying coil that has n turns, such that the field produced at any point is n times as large as that produced by a single turn.

Q13.  You are given the following current-time graphs from two different sources:

Magnetism_03

Now, answer the following questions:

(i)  Name the type of current in two cases.

(ii)  Identify any one source for each type of these currents.

(iii) What is the frequency of current in case (b) in India?

 (iv)  Use above graphs to write two differences between the current in two cases.

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