12<\/sup>
\nb. An electric dipole is a pair of equal and opposite point charges +q and -q separated by a distance r. Write an expression for its dipole moment.
\nc. When an electric dipole is subjected to a uniform electric field, what will happen?<\/p>\nQuestion 6.
\nA message signal of frequency 10kHz and peak voltage 10V is used to modulate a carrier of frequency 1 MHz and peak voltage 20V. Find the modulation index.<\/p>\n
Question 7.
\na. Resistivity of a conductor depends upon
\n(i) its material
\n(ii) its cross-sectional area
\n(iii) its length
\n(iv) All of the above
\nb. Calculate the current flowing through the following circuit :
\n
\nc. A potentiometer is a device to measure emf of a cell. Explain how the emfs of two cells can be compared using a potentiometer.<\/p>\n
Question 8.
\na. Choose the wrong option.
\n(i) Volt = Weber \/ second
\n(ii) Weber = Henry x Ampere
\n(iii) Joule = Henry x Ampere\u00b2
\n(iv) Volt = Weber x Second
\nb. The current in a coil of self-inductance 0.1 H varies from 2A to 5A in a time of 1ms. Find the induced emf across the coil.<\/p>\n
Question 9.
\na. Sound waves do not exhibit
\ni. interference
\nii. diffraction
\niii. polarization
\niv. reflection
\nb. Describe Young\u2019s double-slit experiment to determine the bandwidth of the interference pattern.
\nOR
\na. The intensity of scattered light I in Rayleigh scattering is proportional to……
\nb. Explain the diffraction pattern obtained due to a single slit and represent graphically the variation of intensity with angle of diffraction.<\/p>\n
Question 10.
\na. Define half-life period of a radioactive nucleus. Write down the relation connecting half-life period and mean life.
\nb. Define 1 amu. Calculate its energy equivalent in MeV.<\/p>\n
Question 11.
\nPhotoelectric current does not depend on energy of the radiation, but on its intensity. Explain?<\/p>\n
Question 12.
\na. Speed of light in glass is 2 x 108<\/sup> m\/s. The Refractive index of glass is……
\nb. For an equilateral prism made of a material of refractive index \u221a2 . find the angle of minimum deviation for a ray of monochromatic light.
\nc. Draw the ray diagram of a simple microscope that uses a single convex lens. Derive an expression for its linear magnification.<\/p>\nQuestion 13.
\na. A dielectric slab is placed between the plates of a parallel plate capacitor. Its capacitance
\ni. becomes zero
\nii. remains the same
\niii. decreases
\niv. increases
\nb. Derive an expression for energy stored in a capacitor.<\/p>\n
Question 14.
\na. At resonance, in an LCR circuit, the emf and current are
\n(i) in phase
\n(ii) out of phase
\n(iii) having a phase difference of \\(\\frac { \\pi }{ 2 } \\)
\n(iv) having a phase difference of \\(\\frac { \\pi }{ 6 } \\)
\nb. In the following circuit, find the value of V
\n
\nOR
\na. In a circuit carrying an ideal coil with negligible resistance, the power dissipated is …….
\nb. In the following circuit, find the impedance.
\n<\/p>\n
Question 15.
\nExplain hysteresis and draw hysteresis curve for a ferromagnetic substance.<\/p>\n
Question 16.
\nChoose the appropriate values for X-rays from the given table.
\n<\/p>\n
Question 17.
\na. Unit of wavenumber is
\ni. Hz
\nii. eV
\niii. m
\niv. m-1<\/sup>
\nb.Energy of ground state of a hydrogen atom is -13.6 eV. What is its ionization potential?<\/p>\nQuestion 18.
\nThe current amplification factor for CB configuration of a transistor is 0.9. Find out the current amplification ion factor for CE configuration.<\/p>\n
Question 19.
\na. An electric charge q is moving with a velocity v in the direction of a magnetic field B. The magnetic force acting on the charge is
\n
\nb. starting from Biot – Savart law, obtain an expression for the magnetic field at an axial point of a circular coil carrying current.
\nOR
\na. An ammeter is a current measuring device which is always connected in an electric circuit.
\nb. Describe a cyclotron and obtain an expression for cyclotron frequency.<\/p>\n