Definitions [3]
Define ampere.
Current passed through each of the two infinitely long parallel straight conductors kept at a distance of one meter apart in vacuum causes each conductor to experience a force of 2 × 10-7 newton per meter length of the conductor.
Define the term ‘current sensitivity’ of a moving coil galvanometer.
The current sensitivity of a galvanometer is defined as the deflection produced in the galvanometer when a unit current flows through it.
Mathematically, it can be given by:
IS = `(NBA)/k`
Where k is the couple per unit twist.
Current sensitivity is defined as the deflection e per unit current.
A device used to accelerate positively charged particles (α particles, deutrons, protons, etc.) to acquire enough energy to carry out nuclear disintegration is called a cyclotron.
Formulae [5]
\[\mathrm{C.S.}=\frac{\theta}{I}=\frac{NBA}{C}\]
\[\mathrm{V.S.}=\frac{\theta}{V}=\frac{NBA}{CR}\]
mv = p = q BR
fa = fc
Final energy in cyclotron: proportional to \[\ R_{exit}^2\]
Theorems and Laws [2]
This law states that the line integral of magnetic field density (B) along an imaginary closed path is equal to the product of the current enclosed by the path and the permeability of the medium.
\[\oint\vec{B}.\overrightarrow{dl}=\mu_{0}I\]
The line integral of magnetic field of induction \[\vec B\] around any closed path in free space equals μ0 times the total current through the area bounded by the path.
∮\[\vec B\] ⋅ \[\vec d\]s = μ0I. The closed loop is called an Amperian loop; I is the net current enclosed.
Applications
- Magnetic field due to a long straight current-carrying wire.
- Magnetic field inside an ideal long straight solenoid.
- Magnetic induction along the axis of a toroid.
Key Points
Based on the torque on the current-carrying coil in the magnetic field: \[\tau=NIAB\]
Restoring torque: \[\tau=C\theta\]
At equilibrium: \[NIAB=C\theta\]
- Electric field accelerates the particle; magnetic field keeps it in circular orbit of constant frequency.
- Resonance: polarity of Ds reverses as ion crosses gap after each semicircle.
- Cannot accelerate neutrons (uncharged) or electrons (small mass, high velocity).
- Ion speed is limited.
Important Questions [23]
- Obtain an Expression for Magnetic Induction Along the Axis of Toroid.
- Explain Ampere’S Circuital Law.
- State Ampere’S Circuital Law.
- State Ampere’s circuital law.
- Obtain the Expression for Current Sensitivity of Moving Coil Galvanometer.
- To convert a moving coil galvanometer into an ammeter we need to connect a ______.
- Calculate the Sensitivity of the Moving Coil Galvanometer
- A Circular Coil of 250 Turns and Diameter 18 Cm Carries a Current Of 12a. What is the Magnitude of Magnetic Moment Associated With the Coil?
- A Moving Coil Galvanometer Has a Resistance of 25ω and Gives a Full Scale Deflection for a Current of 10ma. How Will You Convert It into a Voltmeter Having Range 0 - 100 V?
- An Ideal Voltmeter Has ?
- A Galvanometer Has a Resistance of 16ω. It Shows Full Scale Deflection, When a Current of 20 Ma is Passed Through It. the Only Shunt Resistance Available is 0.06 Which is Not Ap
- The Combined Resistance of a Galvanometer of Resistance 500Ω and Its Shunt is 21Ω. Calculate the Value of Shunt
- Explain How Moving Coil Galvanometer is Converted into a Voltmeter. Derive the Necessary Formula.
- A Rectangular Coil of a Moving Coil Galvanometer Contains 100 Turns, Each Having Area 15 cm^2. It is Suspended in the Radial Magnetic Field 0.03 T.
- The Fraction of the Total Current Passing Through the Galvanometer is ............ .
- Show that the Current Flowing Through a Moving Coil Galvanometer is Directly Proportional to the Angle of Deflection of Coil.
- State how a moving coil galvanometer can be converted into an ammeter.
- If a watch-glass containing a small quantity of water is placed on two dissimilar magnetic poles, then water ______.
- Which One of the Following Particles Cannot Be Accelerated by a Cyclotron?
- In a Cyclotron, Magnetic Field of 3·5wb/m^2 is Used To Accelerate Protons. What Should Be the Time Interval In Which the Electric Field Between the Dees Be Reversed?
- Draw a Neat Labelled Diagram for the Construction of 'Cyclotron'
- A Cyclotron is Used to Accelerate Protons to a Kinetic Energy of 5 Mev. If the Strength of Magnetic Field in the Cyclotron is 2t, Find the Radius and the Frequency Needed for the Applied Alternating
- Cyclotron is used to accelerate ______.
