What is meant by magnetic field?
How is the direction of magnetic field at a point determined?
Draw a diagram to show magnetic field due to a bar magnet in a given region.
Identify the poles of a magnet in the figure.
What does the degree of closeness of magnetic field lines near the poles signify?
State the conclusions that can be drawn from the observation that a current carrying wire deflects a magnetic needle placed near it.
The diagram given below represents the magnetic field caused by a current-carrying conductor. Identify the nature of the coil.
Identify the region, where the magnetic field around a current carrying solenoid is uniform.
State the direction of the magnetic field in the following case.
Name the rule which gives the direction of induced current in a conductor.
Under what orientation, the induced current produced in moving conductor in a magnetic field can be maximum?
How is induced current in a secondary coil related to current in a primary coil?
Why is an alternating current considered to be advantageous over direct current for long range transmission of electric energy?
An alternating current has frequency of 50 Hz. How many times does it change its direction in one second?
How is the type of current that we receive in domestic circuit different from one that runs a clock?
In a domestic electric circuit, mention the potential difference between live wire and neutral wire and frequency of AC?
How should the electric lamps in a building be connected, so that the switching on or off in a room has no effect on other lamps in the same building?
What is the advantage of third wire of the earth connection in domestic electrical application?
Which is the most important safety method used for protecting home appliances from short circuiting or overloading?
A region A has magnetic field lines relatively closer than another region B. Which region has stronger magnetic field? Give reason to support your answer.
What does the divergence of magnetic field lines near the ends of a current carrying straight solenoid indicate?
A horizontal power line carries a current from East to West direction. What is the direction of the magnetic field due to the current in the power line at a point above and at a point below the power line?
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?
State what would happen to the direction of rotation of a motor, if
(i) the current were reversed?
(ii) both current and magnetic field were reversed simultaneously?
(i) The diagram shows a bar magnet surrounded by four plotting compasses. Copy the diagram and mark the direction of the compass
needle for each of the cases B, C and D.
(ii) Which is the North pole, X or Y?
A plotting compass is placed inside a solenoid and the compass needle is pointing in the direction as shown.
(i) Complete the diagram by drawing arrowheads to indicate the direction of the current flow.
(ii) Describe the direction of the magnetic field inside the solenoid.
The wire in the figure below is being moved downwards through the magnetic field, so as to produce induced current.
What would be the effect of
(i) moving the wire at a higher speed?
(ii) moving the wire upwards rather than downwards?
(iii) using a stronger magnet?
(iv) holding the wire still in the magnetic field?
The given figure shows a DC motor model used by a student to study electromagnetism.
The two ends of the coil are fixed to a pair of curve elastic metal strips. The metal strips are connected to the power supply with a rheostat.
(i) State the direction of rotation of the coil when viewed from the front.
(ii) The student is still testing on the feasibility of using the metal strips in the model. What is he trying to achieve?
The figure shows the split ring commutator and the two carbon brushes in their respective positions.
What can you say about the carbon brush spilled ring commutator?
What are magnetic field lines? Justify the following statements.
(i) Two magnetic field lines never intersect each other.
(ii) Magnetic field lines are closed curves.
State the purpose for which the following rules are used
(i) Right hand thumb rule
(ii) Fleming's left hand rule
(iii) Fleming's right hand rule
Describe an activity with diagram to demonstrate the presence of magnetic field around a current carrying straight conductor.
The flow of current in a circular wire creates a magnetic held at its centre. How can existence of this field be detected? State the rule which helps to predict the direction of magnetic field.
Meena draws magnetic field lines of the field close to the axis of a current-carrying circular loop. As she mo s away from the centre of the circular loop she observes that the lines keep on diverging. How will you explain her observations?
Find the direction of magnetic field due to a current-carrying circular coil held:
(i) Vertically in the North-South plane and an observer looking it from East sees the current to flow in the anti-clockwise direction.
(ii) Vertically in East-West plane and an observer looking it from South sees the current to flow in the anti-clockwise direction.
(iii) Horizontally and an observer looking at it from below sees current to flow in the clockwise direction.
The diagram shows the lengthwise section of a current-carrying solenoid.
Indicates current entering into the page,
indicates current emerging out of the page.
Decide which end of the solenoid A or B, behave as North pole. Give a reason for our answer. Also, draw field lines inside the solenoid.
For the current-carrying solenoid as shown below, draw magnetic field lines and give reason to explain that out of the three points A, B, and C at which point the field strength is maximum and at which point it is minimum.
A circular metallic loop is kept above the wire AB as shown bélow:
What is the direction of induced current produced in the loop, if any when the current flowing in the straight wire
(i) is steady, i.e. does not vary?
(ii) is increasing in magnitude?
Justify your answer in each case.
A copper coil is connected to a galvanometer. What would happen, if a bar magnet is
(i) pushed into the coil with it's North pole entering first?
(ii) held at rest inside the coil?
(iii) pulled out again?
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.
A magnetic compass needle is placed in the plane of paper near point A as shown in the figure. In which plane should a straight current-carrying conductor be placed, so that it passes through A and there is no change in the deflection of the compass? Under what condition is the deflection maximum and why?
(i) Two circular coils P and Q are kept close to each other, of which coil P carries a current. If coil P is moved towards Q, then will some current be induced in coil Q? Give a reason for your answer and name the phenomenon involved.
(ii) What happens, if coil P is moved away from Q?
(iii) State a few methods of inducing a current in a coil.
List two distinguishing features between overloading and short-circuiting.
What is an electric fuse? What is its role in electric circuits? Should it be placed on neutral wire or on the live wire? Justify your answer.
(i) Describe an activity to obtain a magnetic field line around the current-carrying straight conductor.
(ii) State the rule used to find the direction of this magnetic field.
(iii) How does the magnitude of the magnetic field depend on the current through a conductor?
(i) Draw the magnetic field lines through and around a single loop of wire carrying electric current.
(ii) State whether an -particle Will experience any force in a magnetic field, if (a-particles are positively charged
(a) It is placed in the field at rest.
(b) It moves in the magnetic field parallel to field lines.
(c) It is the magnetic field perpendicular to field lines. Justify yours in each case.
Explain with the help of a labelled diagram, the distribution of the 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?
Explain the meanings . of words "electromagnetic" and "induction" in the term electromagnetic induction. List three factors on which the value of induced current produced in a circuit depends.
Name and state the rule used to determine the direction of the induced current. State one practical application of this phenomenon in everyday life.
Draw a labeled circuit diagram Of a simple electric motor and explain its working. In what way these simple electric motors are different from commercial motors?
(i) What is meant by electromagnetic induction? Name one device which works on electromagnetic induction.
(ii) Describe three different ways to produce induced current in a coil of wire.
Differentiate between AC and DC. Name one source of each. write any two advantages of alternating current over direct current.