Ravindra Waykole Sci Phy

IMPORTANT PRACTICE QUESTIONS 12 TH PHYSICS 

HSC MAHARASHTRA BOARD 2024

Chapter 6 to 10

Chapter 6. Superposition of Waves 

1. Equation stationary wave on stretched string and condition of nodes and antinodes ?

2. State the properties of Stationary wave.

3. Distinguish between a) progressive wave and stationary wave 

b) Free and Force vibration?

4. Obtain the expression for the frequency of the first three modes of vibration of stretched string between two rigid support with the help of neat labelled diagram. Hence show that all harmonics are present  in these vibrations.

5. Draw the neat labelled diagram of the first three modes of vibration of air column in a pipe open at one end (or closed at one end). 

Obtain the formule for the frequency of the first three modes of  vibration of air column in the same pipe. Also in this case show that odd harmonics are present. 

6. Obtain an expression for the frequency of the first three modes of vibration of air column in the pipe open at both end with neat labelled diagram. Also in this case show that even harmonics are present. 

7. Show that the fundamental frequency of vibration of the air column in a pipe open at both ends is double that of a pipe of the same length and closed at one end.

8. Two organ pipes closed at one end have the same diameters but different lengths. Show that the end correction at each end is where the symbols have their usual meanings.

9. What are beats? Define (1) the period of beats (2) beat frequency.

10. Explain the production of beats and deduce analytically the expression for beat frequency.

                    OR 

 Discuss analytically the formation of beats and show that 

(1) the beat frequency equals the difference in frequencies of two interfering waves

(2) the waxing and waning occur alternately and with the same period.

11. Explain any two applications of beats.

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Chapter 7. Wave Optics

1 Give a brief account of Huygens’ wave theory of light. State its merits and demerits.

2. State Huygens’ principle.

3. Explain the construction and propagation of a plane wavefront using Huygens’ principle.

4. Explain the construction and propagation of a spherical wavefront using Huygens’ principle.

5.Explain the phenomenon of polarization of light by reflection. 

                      OR 

   Explain Brewster’s law.

6. Describe with a neat labelled ray diagram the Fraunhofer diffraction pattern due to a single slit. Obtain the expressions for the positions of the intensity minima and maxima. Also obtain the expression for the width of the central maximum.

7. In Young’s double-slit experiment, a glass slide of refractive index ng and thickness b is placed in front of one of the slits. 

What happens to the interference pattern and fringe width ?

 Derive an expression for the positions of the bright fringes in the interference pattern.

8. State and explain Rayleigh’s criterion for minimum resolution.

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PART 4

Chapter 8. Electrostatics 

1.Obtain an expression for the electric field intensity at a point outside a charged conducting spherical shell.

Hence, obtain an expression for the electric intensity 

(i) on the surface of (i.e. just outside) the spherical conductor. 

(ii) inside the spherical conductor.

2. Obtain an expression for the electric field intensity at a point outside an infinitely long charged cylindrical conductor.

3. Obtain an expression for the electric field intensity at a point outside a uniformly charged thin infinite plane sheet.

4. Obtain an expression for the electric potential energy of a system of two isolated point charges.

5. Obtain an expression for the electric potential at a point due to an isolated point charge.

6. Derive an expression for the electric potential at a point due to a short electric dipole. Hence, write the expression for the electric potential at a point 

(i) on the dipole axis 

(ii) on the dipole equator.

7. Derive an expression for the potential energy of a system of two point charges.

8. Obtain an expression for the potential energy of a configuration of N point charges.

9. Derive an expression for the electric potential energy of an electric dipole in a uniform electric field. 

                        OR

Derive an expression for the total work done in rotating an electric dipole through an angle θ in a uniform electric field.

10. Derive an expression for the effective or equivalent capacitance (capacity) of a combination of a number of capacitors connected in series.                          OR

Derive an expression for the effective capacitance of three capacitors connected in series.

11. Explain the effect of a dielectric on the capacitance of a isolated charged parallel-plate capacitor.

Hence, show that if a dielectric of relative permitivity (dielectric constant) k completely fills the space between the plates, the capacitance increases by a factor k.

12. Show that the energy of a charged capacitor is 1/2 CV². Also, express this in other forms. 

                         OR

Derive an expression for the energy stored in a charged capacitor. Express it in different forms.

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Chapter 9. Current Elecricity

1 State Kirchhoff’s first law or current law or junction law.

2. What is the sign convention used for Kirchhoff’s first law? Explain with an example.

3. What is the sign convention used for Kirchhoff’s first law? Explain with an example.

4. What is the sign convention used for Kirchhoff’s second law ? Explain with an example.

5. Obtain the balancing condition in case of Wheatstone’s network.

6. Explain with the help of neat circuit diagram, how you determine the unknown resistance by using a meter-bridge.

7. Describe how a potentiometer is used to compare the emfs of two cells by combination method.

8. Describe with the help of a neat circuit diagram how you will determine the internal resistance of a cell by usinhg a potentiometer.

9. State the advantages of a potentiometer over a voltmeter.

10. Explain how a moving-coil galvanometer is converted into an ammeter. Derive the necessary formula.

11. Explain how a moving-coil galvanometer is converted into a voltmeter. Derive the necessary formula.

12. Distinguish between an ammeter and a voltmeter.

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PART 5

Chapter 10. Magnetic Fields due to Eletric Current 

1 (a) State the factors which the magnetic force on a charge depends upon and write its vector cross product relationship. 

    (b) Hence state the expression for the Lorentz force on a charge due to an electric field as well as a magnetic field.

    (c) Hence discuss the magnetic force on a charged particle which is

(i) moving parallel to the magnetic field (ii) stationary.

2. Define the SI unit of magnetic induction from Lorentz force.

3. Obtain an expression for the magnetic force acting on the straight wire carrying a current. Also extend this formula for a wire of arbitrary shape. 

4. Derive an expression for the net torque on a rectangular current-carrying loop placed in a uniform magnetic field with its rotation axis perpendicular to the field.

5. Describe the construction of a suspended-type moving-coil galvanometer with a neat labelled diagram.

6. State working of a moving- coil galvanometer (suspended-coil type).

7. State the Bio-Savart law (Laplace law) for the magnetic induction produced by a current el-ement. Express it in vector form.

8. Using Biot-Savart’s law, obtain the expression for the magnetic induction near a straight infinitely long current-carrying wire.

9. Show that currents in two long, straight, parallel wires exert forces on each other. Derive the expression for the force. 

                      OR

    Derive an expression for the force per unit length between two infinitely long parallel conductors carrying current and hence define the ampere.

10. Obtain an expression for the magnetic induction produced by a current in a wire in the shape of a circular arc at its centre of curvature. 

Hence obtain an expression for the magnetic induction at the centre of a circular coil carrying a current.

11. Derive an expression for the magnetic induction at a point on the axis of a circular coil carrying a current.

12. State and explain Ampere’s circuital law.

13. Using Ampere’s law, obtain an expression for the magnetic induction near a current-carrying straight, infinitely long wire.

14. Using Ampere’s law, derive an expression for the magnetic induction inside an ideal solenoid carrying a steady current.

15. Using Ampere’s law, derive an expression for the magnetic induction inside an ideal toroid carrying a steady current.

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