# MAGNETIC EFFECTS OF ELECTRIC CURRENT – 3 Mark Questions

Q1.  How does the strength of magnetic field due to a current-carrying conductor depend upon

(i)  distance from-the conductor?

(ii)   current flowing through the conductor?

Q2. Under what conditions permanent electromagnet is obtained, if a current-carrying solenoid is used?  Support your answer with the help of a labelled circuit diagram.

Q4.  What is an electric fuse?  What is its role in electric circuits? Should it be placed on neutral wire or on live wire?  Justify your answer.

Q5. What does the magnetic field pattern inside the solenoid indicate? State how this field be utilised to make an electromagnet. List two ways by which strength of this magnet can be increased.

Q6. Explain briefly two different ways to induce current in a coil. State the rule which determines the direction of induced current.

Q7. Explain whether an alpha particle will experience any force in a magnetic field if:

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

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

(iii) It moves in the magnetic field perpendicular to field lines.

Q8. How would the strength of magnetic field due to current carrying loop be affected if:

(i) Radius of the loop is reduced to half its original value?

(ii) Strength of current through the loop is doubled?

Q9. What is short-circuiting?   State one factor/condition that can lead to it. Name a device in the household that acts as a safety measure for it. State the principle of its working.

Q10. (a) Give the significance of the following in a domestic circuit:

(i) Electric meter

(ii) Earthing

Q11. List three factors which can cause overloading of domestic electric circuits.

Q12. 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.

Q13.  (i) What do you understand by the term short circuit? How does it occur?

(ii) What are the consequences of short circuit?

(iii) Give two examples for application of heating effect of electric current.

Q14.      A magnet AB is broken into two pieces. Point out the polarity of A, B, C and D. Q15.  A small valued resistance XY is connected across the ends of a coil. Predict the direction of induced current in the resistance XY when (i)  South pole of a magnet moves towards end A of the coil.

(ii)  South pole of a magnet moves away from end A of the coil.

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