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A magnet kept at the centre of two coils A and B is moved to and fro as shown in the diagram. The two galvanometers show deflection. State with a reason whether : x > y or x< y [x and y are magnitudes of deflection.]
Concept: Applications of Biot-Savart's Law > Magnetic Field at the Centre of a Circular Loop
Draw a neat labeled diagram of an A.C. generator
Concept: A.C. Generator
A coil has a self-inductance of 0·05 Henry. Find the magnitude of the emf induced in it when the current flowing through it is changing at the rate of 100 As-1.
Concept: Electromagnetic Induction
Why is the core of a transformer made of soft iron?
Concept: Transformers
The diagram below shows a free conductor AB is kept in a magnetic field and is carrying current from A to B. (To avoid confusion complete path of the circuit is not shown) The direction of the force experienced by the conductor will be:
Concept: Force on a Current Carrying Conductor in a Magnetic Field
The diagram below shows a magnet moved near a coil along its axis. Which of the diagram shows correct flow of current during this motion?
Concept: Applications of Ampere’s Circuital Law > Magnetic Field of a Long Straight Solenoid
The diagram below shows an insulated copper wire wound around a hollow cardboard cylindrical tube. Answer the questions that follow:
- What are the magnetic poles at A and B when the key K is closed?
- State two ways to increase the strength of the magnetic field in this coil without changing the coil.
- If we place a soft iron bar at the centre of the hollow cardboard and replace the DC source with an AC source then will it attract small iron pins toward itself when the current is flowing through the coil?
Concept: Applications of Ampere’s Circuital Law > Magnetic Field of a Long Straight Solenoid
Name one electrical device which works on Faraday's law of electromagnetic induction principle.
Concept: Transformers
If the strength of the current flowing through a wire is increased, the strength of the magnetic field produced by it ______.
Concept: Force on a Current Carrying Conductor in a Magnetic Field
A copper conductor is placed over two stretched copper wires whose ends ate connected to a D.C. supply as shown in the diagram.
- What should be the magnetic poles at the points A and B lying on either side of the conductor to experience the force in the upward direction?
- Name the law used to find these polarities.
Concept: Force on a Current Carrying Conductor in a Magnetic Field
State two factors affecting the coil's rotation speed in a D.C. motor.
Concept: Simple D.C. Motor
State one factor that affects the magnitude of induced current in an AC generator.
Concept: A.C. Generator
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Given below is a circuit to study the magnetic effect of electric current. ABCD is a cardboard kept perpendicular to the conductor XY. A magnetic compass is placed at the point P of the cardboard. P1 and P2 are the positions of the magnetic compass, before and after passing a current through XY respectively.
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- Name the rule that is used to predict the direction of deflection of the magnetic compass.
- State the direction of current in the conductor (X to Y or Y to X) when the circuit is complete.
- If resistance R is increased, then what will be the effect on the magnetic lines of force around the conductor?
Concept: Right-hand Thumb Rule
Current is flowing through a coil as shown in the figure. Which one of the given figures will correctly depict the magnetic polarity and the direction of the lines of force along the axis of the coil?
Concept: Applications of Ampere’s Circuital Law > Magnetic Field of a Long Straight Solenoid
Name the principle of AC generator.
Concept: Faraday's Laws of Electromagnetic Induction
State the use of the principle of electromagnetic induction.
Concept: Faraday's Laws of Electromagnetic Induction
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The graph (fig A) illustrates the correlation between the number of protons (x-axis) and the number of neutrons (y-axis) for elements A, B, C, D, and E in the periodic table. These elements are denoted by the letters rather than their conventional symbols. When the element C, depicted in the graph, undergoes radioactive decay, it releases radioactive rays. When these rays are directed into the plane of the paper in the presence of a magnetic field, as indicated in the fig B, they experience deflection, causing them to move upwards.
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Name the law used to identify the radioactive radiation emitted by the element.
Concept: Force on a Current Carrying Conductor in a Magnetic Field
Define heat capacity and state its SI unit.
Concept: Specific Heat Capacity
A solid of mass 50 g at 150 °C is placed in 100 g of water at 11 °C when the final temperature recorded is 20 °C. Find the specific heat capacity of the solid. (specific heat capacity of water = 4.2 J/g °C)
Concept: Specific Heat Capacity
You have a choice of three metals A, B, and C, of specific heat capacities 900 Jkg-1 °C-1, 380 Jkg-1 °C-1 and 460 Jkg-1 °C-1 respectively, to make a calorimeter. Which material will you select? Justify your answer.
Concept: Specific Heat Capacity
