Standard 10th Science Experiment 4 Answer Solutions: Study of the magnetic field produced by an electric current flowing through a coil of copper wire Answers and Solutions.
Aim :
To study the magnetic field produced by an electric current flowing through a coil of copper wire.
Requirements :
A 12 V battery, insulated copper wire (gauge 24), connecting wires, variable resistance, plugkey, a cardboard or plastic sheet, iron filings, a magnetic needle, a hollow tube or cylinder of cardboard.
Procedure :
(1) Make a coil of insulated copper wire by winding 20 to 25 turns of the wire around a hollow tube orcylinder of cardboard. (2) Pass this coil through a horizontal cardboard or plastic sheet as illustrated in the diagram. (3) Connect the free ends of the wire in a circuit containing a variable resistance, ammeter, 12 V battery andplug key as shown in the diagram. (4) Spread iron filings on the cardboard or the plastic sheet. (5) Close the plug key to pass the electric current through the coil. (6) Tap the cardboard lightly with a finger and observe the arrangement of iron filings. (7) Increase the current in the coil gradually by decreasing the resistance in the circuit and observe how thearrangement of iron filings changes.
Diagram :
Label the various components in the given diagram.
Observations :
- Iron filings form concentric circular paths. These concentric circles represent magnetic lines of force.
- As we go away from the wire, the concentric circles representing the magnetic lines of force become bigger and bigger
- As the electric current through the coil increases, the intensity of the magnetic field also increases and the lines of force are seen more distinctly.
Inferences / Conclusions :
- When the current flows through the coil, magnetic lines of force produced at each point around thecopper wire forming the coil.
- At a given point on the cardboard, the magnetic field produced by the current flowing through the coilis directly proportional to the current and the number of turns forming the coil
Precaution:
Connect the various components in the electric circuit properly.
.
Multiple Choice Questions
Choose the correct alternative and write its letter (A), (B), (C), (D) in the box :
Intensity of magnetic field is expressed in .
(A) ampere (B) volt (C) coloumb (D) oersted
Answer: D
2. The direction of the magnetic field around a straight conductor carrying current is given by .
(A) the right hand thumb rule (B) Fleming’s left hand rule (C) Fleming’s right hand rule (D) Coulomb’s rule
Answer: A
3. is used to determine the presence and direction of magnetic field.
(A) The voltmeter (B) An ammeter (C) A galvanometer (D) The magnetic needle
Answer: D
4. In this experiment, the magnetic field at a point on the cardboard depends .
(A) only on the current (I) (B) only on the number of turns (n) in the coil (C) only on the distance (r) of the point from the wire (D) on all of these, i.e. I, n and r
Answer: D